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19 votes
3 answers
2k views

Cyclotomic polynomials: $\Phi_n(p)$ is like $p^{\phi(n)}$ for big enough $p$, right?

Apologies in advance if this turns out to be simple. So far I haven't found a proof or a reference. Although I like $p$ to be a prime, I can ask the following for positive integers $n$ and $p$, ...
Gerhard Paseman's user avatar
31 votes
7 answers
6k views

English reference for a result of Kronecker?

Kronecker's paper Zwei Sätze über Gleichungen mit ganzzahligen Coefficienten apparently proves the following result that I'd like to reference: Let $f$ be a monic polynomial with integer ...
Gray Taylor's user avatar
17 votes
1 answer
3k views

Is $x^{n}-x-1$ irreducible?

Is it true that for every $n \in \mathbb{N}$, $x^{n}-x-1$ is irreducible in $\mathbb{Z}[x]$? The standard irreducibility criteria seem to fail.
Pablo's user avatar
  • 11.3k
5 votes
1 answer
351 views

Divisibility of certain polynomials

Consider the finite sums $$F_n(q)=\sum_{k=1}^nq^{\binom{k}2}$$ with exponents the triangular numbers $\binom{k}2$. When $n$ is odd, it appears that $F_n(q)$ does not factorize over $\mathbb{Z}[q]$. On ...
T. Amdeberhan's user avatar
5 votes
0 answers
775 views

A conjecture about the degrees of special polynomials

Define the congruence "modulo m" on exponential Taylor series as $$ \sum_{n=0}^\infty \frac{a_n}{n!}x^n \equiv \sum_{n=0}^\infty \frac{b_n}{n!} x^n \mod m \iff \forall n: \frac{a_n-b_n}{m}\in \mathbb{...
Danil Krotkov's user avatar
3 votes
1 answer
447 views

A number array related to colored necklaces and the primes

I stumbled upon entry OEIS-A208535 on the enumeration of certain kinds of colored necklaces and noticed that the integers for the odd prime rows of the table there seem to be given by the Moreau ...
Tom Copeland's user avatar
  • 10.5k