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Sebastien Palcoux
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Regarding Feit-Thompson Conjecture [FT62] mentioned in Dave Benson's answer, which states that for any two distinct odd primes $p$ and $q$, the integer $\frac{p^q - 1}{p - 1}$ never divides $\frac{q^p - 1}{q - 1}$, I am unsure to what extent this has been verified. Below is a (parallelized) Python script that confirms the conjecture holds for $p, q < 50000$ within 35 hours. It also identifies the pair $(p, q) = (17,3313)$, discovered in [S71], as noted in JoshuaZ's comment, for the sole non-coprime example in this range. The range could be significantly improveimproved by the method in this paper[S71].

AnBonus question: Is there any other checkingpair $(p,q)$ of this kind?

More recent checkings can be found in Guy's book (Unsolved Problems in Number Theory),[G04] at B25 on page 125:

enter image description here

The last ckecking mentioned above is [DK04]. See also [M09].

Bonus questionReferences

[FT62] Feit, Walter; Thompson, John G. A solvability criterion for finite groups and some consequences. Proc. Nat. Acad. Sci. U.S.A. 48 (1962), 968--970.
[S71] Stephens, N. M. On the Feit-Thompson conjecture. Math. Comp. 25 (1971), 625.
[DK04] Dilcher, Karl; Knauer, Joshua. On a conjecture of Feit and Thompson. High primes and misdemeanours: Is there any other such pairlectures in general?honour of the 60th birthday of Hugh Cowie Williams, 169--178, Fields Inst. Commun., 41, Amer. Math. Soc., Providence, RI, 2004.
[G04] Guy, Richard K. Unsolved problems in number theory. Third edition. Problem Books in Mathematics. Springer-Verlag, New York, 2004. xviii+437 pp.
[M09] Motose, Kaoru. Notes on the Feit-Thompson conjecture. Proc. Japan Acad. Ser. A Math. Sci. 85 (2009), no. 2, 16--17.

 

Regarding Feit-Thompson Conjecture mentioned in Dave Benson's answer, which states that for any two distinct odd primes $p$ and $q$, the integer $\frac{p^q - 1}{p - 1}$ never divides $\frac{q^p - 1}{q - 1}$, I am unsure to what extent this has been verified. Below is a (parallelized) Python script that confirms the conjecture holds for $p, q < 50000$ within 35 hours. It also identifies the pair $(p, q) = (17,3313)$ as noted in JoshuaZ's comment, for the sole non-coprime example in this range. The range could be significantly improve by the method in this paper.

An other checking can be found in Guy's book (Unsolved Problems in Number Theory), at B25 on page 125:

enter image description here

Bonus question: Is there any other such pair in general?

 

Regarding Feit-Thompson Conjecture [FT62] mentioned in Dave Benson's answer, which states that for any two distinct odd primes $p$ and $q$, the integer $\frac{p^q - 1}{p - 1}$ never divides $\frac{q^p - 1}{q - 1}$, I am unsure to what extent this has been verified. Below is a (parallelized) Python script that confirms the conjecture holds for $p, q < 50000$ within 35 hours. It also identifies the pair $(p, q) = (17,3313)$, discovered in [S71], as noted in JoshuaZ's comment, for the sole non-coprime example in this range. The range could be significantly improved by the method in [S71].

Bonus question: Is there any other pair $(p,q)$ of this kind?

More recent checkings can be found in [G04] at B25 on page 125:

enter image description here

The last ckecking mentioned above is [DK04]. See also [M09].

References

[FT62] Feit, Walter; Thompson, John G. A solvability criterion for finite groups and some consequences. Proc. Nat. Acad. Sci. U.S.A. 48 (1962), 968--970.
[S71] Stephens, N. M. On the Feit-Thompson conjecture. Math. Comp. 25 (1971), 625.
[DK04] Dilcher, Karl; Knauer, Joshua. On a conjecture of Feit and Thompson. High primes and misdemeanours: lectures in honour of the 60th birthday of Hugh Cowie Williams, 169--178, Fields Inst. Commun., 41, Amer. Math. Soc., Providence, RI, 2004.
[G04] Guy, Richard K. Unsolved problems in number theory. Third edition. Problem Books in Mathematics. Springer-Verlag, New York, 2004. xviii+437 pp.
[M09] Motose, Kaoru. Notes on the Feit-Thompson conjecture. Proc. Japan Acad. Ser. A Math. Sci. 85 (2009), no. 2, 16--17.

 
Bonus question and Improved the bound of the checking of Feit-Thompson Conjecture from 25000 to 50000 and Quotation of Guy's book for other checking
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Sebastien Palcoux
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Regarding Feit-Thompson Conjecture mentioned in Dave Benson's answer, which states that for any two distinct odd primes $p$ and $q$, the integer $\frac{p^q - 1}{p - 1}$ never divides $\frac{q^p - 1}{q - 1}$, I am unsure to what extent this has been verified. Below is a (parallelized) Python script that confirms the conjecture holds for $p, q < 25000$$p, q < 50000$ within 90 minutes35 hours. It also identifies the pair $(p, q) = (17,3313)$ as noted in JoshuaZ's comment, for the sole non-coprime example in this range. The range could be significantly improve by the method in this paper.

An other checking can be found in Guy's book (Unsolved Problems in Number Theory), at B25 on page 125:

enter image description here

Bonus question: Is there any other such pair in general?

    ...$time python3 check_primes_parallel.py
Pair not relatively prime: p=17, q=3313, gcd=112643

real    88m572066m4.158s640s
user    838m4413490m17.435s916s
sys 0m91m1.762s613s
# check_primes_parallel.py
from sympy import primerange, gcd
from multiprocessing import Pool
import itertools

def check_relative_prime_and_divisibility(pair):
    p, q = pair
    num1 = (pow(p, q) - 1) // (p - 1)
    num2 = (pow(q, p) - 1) // (q - 1)
    
    d = gcd(num1, num2)
    if d == 1:
        return None
    
    if num1 % num2 == 0:
        return f"Found divisible pair: p={p}, q={q}"
    else:
        return f"Pair not relatively prime: p={p}, q={q}, gcd={d}"

def find_prime_pairs(max_prime, num_cpus=12num_cpus=8):
    # Generate a list of odd primes up to max_prime
    primes = list(primerange(3, max_prime))
    
    # Generate all unique combinations of two primes
    prime_pairs = list(itertools.combinations(primes, 2))

    # Create a pool of workers with the desired number of CPUs
    with Pool(processes=num_cpus) as pool:
        # Map the function over the prime pairs, distributed across the workers
        results = pool.map(check_relative_prime_and_divisibility, prime_pairs)
    
    # Filter out None results and print the rest
    for result in filter(None, results):
        print(result)

# Set a maximum prime number limit according to your computational power
max_prime = 2500050000 # You can adjust this value
find_prime_pairs(max_prime)

Regarding Feit-Thompson Conjecture mentioned in Dave Benson's answer, which states that for any two distinct odd primes $p$ and $q$, the integer $\frac{p^q - 1}{p - 1}$ never divides $\frac{q^p - 1}{q - 1}$, I am unsure to what extent this has been verified. Below is a (parallelized) Python script that confirms the conjecture holds for $p, q < 25000$ within 90 minutes. It also identifies the pair $(p, q) = (17,3313)$ as noted in JoshuaZ's comment, for the sole non-coprime example in this range.

    ...$time python3 check_primes_parallel.py
Pair not relatively prime: p=17, q=3313, gcd=112643

real    88m57.158s
user    838m44.435s
sys 0m9.762s
# check_primes_parallel.py
from sympy import primerange, gcd
from multiprocessing import Pool
import itertools

def check_relative_prime_and_divisibility(pair):
    p, q = pair
    num1 = (pow(p, q) - 1) // (p - 1)
    num2 = (pow(q, p) - 1) // (q - 1)
    
    d = gcd(num1, num2)
    if d == 1:
        return None
    
    if num1 % num2 == 0:
        return f"Found divisible pair: p={p}, q={q}"
    else:
        return f"Pair not relatively prime: p={p}, q={q}, gcd={d}"

def find_prime_pairs(max_prime, num_cpus=12):
    # Generate a list of odd primes up to max_prime
    primes = list(primerange(3, max_prime))
    
    # Generate all unique combinations of two primes
    prime_pairs = list(itertools.combinations(primes, 2))

    # Create a pool of workers with the desired number of CPUs
    with Pool(processes=num_cpus) as pool:
        # Map the function over the prime pairs, distributed across the workers
        results = pool.map(check_relative_prime_and_divisibility, prime_pairs)
    
    # Filter out None results and print the rest
    for result in filter(None, results):
        print(result)

# Set a maximum prime number limit according to your computational power
max_prime = 25000 # You can adjust this value
find_prime_pairs(max_prime)

Regarding Feit-Thompson Conjecture mentioned in Dave Benson's answer, which states that for any two distinct odd primes $p$ and $q$, the integer $\frac{p^q - 1}{p - 1}$ never divides $\frac{q^p - 1}{q - 1}$, I am unsure to what extent this has been verified. Below is a (parallelized) Python script that confirms the conjecture holds for $p, q < 50000$ within 35 hours. It also identifies the pair $(p, q) = (17,3313)$ as noted in JoshuaZ's comment, for the sole non-coprime example in this range. The range could be significantly improve by the method in this paper.

An other checking can be found in Guy's book (Unsolved Problems in Number Theory), at B25 on page 125:

enter image description here

Bonus question: Is there any other such pair in general?

    ...$time python3 check_primes_parallel.py
Pair not relatively prime: p=17, q=3313, gcd=112643

real    2066m4.640s
user    13490m17.916s
sys 1m1.613s
# check_primes_parallel.py
from sympy import primerange, gcd
from multiprocessing import Pool
import itertools

def check_relative_prime_and_divisibility(pair):
    p, q = pair
    num1 = (pow(p, q) - 1) // (p - 1)
    num2 = (pow(q, p) - 1) // (q - 1)
    
    d = gcd(num1, num2)
    if d == 1:
        return None
    
    if num1 % num2 == 0:
        return f"Found divisible pair: p={p}, q={q}"
    else:
        return f"Pair not relatively prime: p={p}, q={q}, gcd={d}"

def find_prime_pairs(max_prime, num_cpus=8):
    # Generate a list of odd primes up to max_prime
    primes = list(primerange(3, max_prime))
    
    # Generate all unique combinations of two primes
    prime_pairs = list(itertools.combinations(primes, 2))

    # Create a pool of workers with the desired number of CPUs
    with Pool(processes=num_cpus) as pool:
        # Map the function over the prime pairs, distributed across the workers
        results = pool.map(check_relative_prime_and_divisibility, prime_pairs)
    
    # Filter out None results and print the rest
    for result in filter(None, results):
        print(result)

# Set a maximum prime number limit according to your computational power
max_prime = 50000 # You can adjust this value
find_prime_pairs(max_prime)
Title edit, add wiki link to Feit=Thompson conjecture, paralellized the code and checked for p,q < 25000
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Sebastien Palcoux
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Request for explicit Explicit character tables of conjectured, non-existent finite simple groups

Regarding the conjectureFeit-Thompson Conjecture mentioned in Dave Benson's answer, which states that for any two distinct odd primes $p$ and $q$, the integer $\frac{q^p - 1}{q - 1}$$\frac{p^q - 1}{p - 1}$ never divides $\frac{p^q - 1}{p - 1}$$\frac{q^p - 1}{q - 1}$, I am unsure to what extent this has been verified. Below is a (parallelized) Python script that confirms the conjecture holds for $p, q < 5000$$p, q < 25000$ within 290 minutes. It also identifies the pair $(p, q) = (3313,17)$$(p, q) = (17,3313)$ as noted in JoshuaZ's comment, for the sole non-coprime example in this range.

    ...$time python3 check_primescheck_primes_parallel.py
Pair not relatively prime: p=3313p=17, q=17q=3313, gcd=112643

real    2m588m57.001s158s
user    2m4838m44.981s435s
sys 0m00m9.012s762s
# check_primescheck_primes_parallel.py
from sympy import primerange, gcd
from multiprocessing import Pool
import itertools

def check_relative_prime_and_divisibility(p, qpair):
    # Calculate the expressions (p^q - 1)/(p - 1) and (q^p -, 1)/(q -= 1)pair
    num1 = (pow(p, q) - 1) // (p - 1)
    num2 = (pow(q, p) - 1) // (q - 1)
    
    # Check if num1 and num2 are relatively prime
    d = gcd(num1, num2)
    if d == 1:
        return FalseNone
    
    #if Ifnum1 they% arenum2 not== relatively0:
 prime       return f"Found divisible pair: p={p}, checkq={q}"
 divisibility   else:
    print(    return f"Pair not relatively prime: p={p}, q={q}, gcd={d}")
    return num2 % num1 == 0

def find_prime_pairs(max_prime, num_cpus=12):
    # Generate a list of odd primes up to max_prime
    primes = list(primerange(3, max_prime))
    
    # Iterate overGenerate all pairsunique combinations of oddtwo primes p, q where p > q
    for iprime_pairs in= rangelist(lenitertools.combinations(primes, 2)): 

    # Create a pool pof =workers primes[i]
with the desired number of CPUs
   #print with Pool(pprocesses=num_cpus) as pool:
        for# jMap inthe range(i):
function over the prime pairs, distributed across the workers
    q    results = primes[j]pool.map(check_relative_prime_and_divisibility, prime_pairs)
     
    # Filter out None ifresults check_relative_prime_and_divisibility(p,and q):print the rest
    for result in filter(None, results):
        print(f"Found divisible pair: p={p}, q={q}"result)

# Set a maximum prime number limit according to your laptop's computational power
max_prime = 500025000 # You can adjust this value
find_prime_pairs(max_prime)

Request for explicit character tables of conjectured, non-existent finite simple groups

Regarding the conjecture mentioned in Dave Benson's answer, which states that for any two distinct odd primes $p$ and $q$, the integer $\frac{q^p - 1}{q - 1}$ never divides $\frac{p^q - 1}{p - 1}$, I am unsure to what extent this has been verified. Below is a Python script that confirms the conjecture holds for $p, q < 5000$ within 2 minutes. It also identifies the pair $(p, q) = (3313,17)$ as noted in JoshuaZ's comment, for the sole non-coprime example in this range.

...$time python3 check_primes.py
Pair not relatively prime: p=3313, q=17, gcd=112643

real    2m5.001s
user    2m4.981s
sys 0m0.012s
# check_primes.py
from sympy import primerange, gcd

def check_relative_prime_and_divisibility(p, q):
    # Calculate the expressions (p^q - 1)/(p - 1) and (q^p - 1)/(q - 1)
    num1 = (pow(p, q) - 1) // (p - 1)
    num2 = (pow(q, p) - 1) // (q - 1)
    
    # Check if num1 and num2 are relatively prime
    d = gcd(num1, num2)
    if d == 1:
        return False
    
    # If they are not relatively prime, check divisibility
    print(f"Pair not relatively prime: p={p}, q={q}, gcd={d}")
    return num2 % num1 == 0

def find_prime_pairs(max_prime):
    # Generate a list of odd primes up to max_prime
    primes = list(primerange(3, max_prime))
    
    # Iterate over all pairs of odd primes p, q where p > q
    for i in range(len(primes)):
        p = primes[i]
        #print(p)
        for j in range(i):
            q = primes[j]
            if check_relative_prime_and_divisibility(p, q):
                print(f"Found divisible pair: p={p}, q={q}")

# Set a maximum prime number limit according to your laptop's computational power
max_prime = 5000 # You can adjust this value
find_prime_pairs(max_prime)

Explicit character tables of non-existent finite simple groups

Regarding Feit-Thompson Conjecture mentioned in Dave Benson's answer, which states that for any two distinct odd primes $p$ and $q$, the integer $\frac{p^q - 1}{p - 1}$ never divides $\frac{q^p - 1}{q - 1}$, I am unsure to what extent this has been verified. Below is a (parallelized) Python script that confirms the conjecture holds for $p, q < 25000$ within 90 minutes. It also identifies the pair $(p, q) = (17,3313)$ as noted in JoshuaZ's comment, for the sole non-coprime example in this range.

    ...$time python3 check_primes_parallel.py
Pair not relatively prime: p=17, q=3313, gcd=112643

real    88m57.158s
user    838m44.435s
sys 0m9.762s
# check_primes_parallel.py
from sympy import primerange, gcd
from multiprocessing import Pool
import itertools

def check_relative_prime_and_divisibility(pair):
    p, q = pair
    num1 = (pow(p, q) - 1) // (p - 1)
    num2 = (pow(q, p) - 1) // (q - 1)
    
    d = gcd(num1, num2)
    if d == 1:
        return None
    
    if num1 % num2 == 0:
        return f"Found divisible pair: p={p}, q={q}"
    else:
        return f"Pair not relatively prime: p={p}, q={q}, gcd={d}"

def find_prime_pairs(max_prime, num_cpus=12):
    # Generate a list of odd primes up to max_prime
    primes = list(primerange(3, max_prime))
    
    # Generate all unique combinations of two primes
    prime_pairs = list(itertools.combinations(primes, 2)) 

    # Create a pool of workers with the desired number of CPUs
    with Pool(processes=num_cpus) as pool:
        # Map the function over the prime pairs, distributed across the workers
        results = pool.map(check_relative_prime_and_divisibility, prime_pairs)
     
    # Filter out None results and print the rest
    for result in filter(None, results):
        print(result)

# Set a maximum prime number limit according to your computational power
max_prime = 25000 # You can adjust this value
find_prime_pairs(max_prime)
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LSpice
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appended answer 460099 as supplemental
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Stefan Kohl
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Became Hot Network Question
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Sebastien Palcoux
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