Jim White

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Name Jim White
Member for 4 months
Seen Feb 20 at 4:46
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Location Canberra, Australia
Age 60
Retired software engineer, now doing computational science research. Special interest in Pell equations, particularly wrt "smooth pairs", ie. the "Størmer Problem", and Lehmer's method of solving it.
Jan
22
comment Decision problem wrt Pairs of Polynomials with Integer Coefficients
If only it were that simple! :)
Jan
22
asked Decision problem wrt Pairs of Polynomials with Integer Coefficients
Jan
20
comment Square Roots of Unity modulo N^2
BTW, I believe the RHS above should be $-2s\lambda$
Jan
18
comment Square Roots of Unity modulo N^2
Thank you very much, that helps, and I can see how it extends to $N^2/f^2$.
Jan
18
comment Square Roots of Unity modulo N^2
If that proviso makes this a trivial question, my apologies, and please could I have a reference?
Jan
18
comment Square Roots of Unity modulo N^2
We can assume N is factorable, ie we know all $f|N$. @Felipe, I don't see how Hensel helps with this specific problem.
Jan
18
revised Square Roots of Unity modulo N^2
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18
asked Square Roots of Unity modulo N^2
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16
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15
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Jan
14
comment a family of Pellian equations
Corrected mistake in the statement "One property shared by all $y_n \in K_1 \ldots $. The divisibility property involves $y_n^2 + 1$, not $y_n$.
Jan
14
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Jan
12
comment Greatest Prime Factors: For any prime p, is there an integer C such that for any x >= C, all but 1 integer in the sequence x+1, x+2, …, x+p has a greatest prime factor > p.
I ask because I've always been interested in investigating an extension to Lehmer's method as described above, but have had no particular motivation to do so.
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12
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Jan
12
comment a family of Pellian equations
Apologies, the bounds for $k$ above should read $2^{32}$ and $2^{64}$
Jan
12
comment a family of Pellian equations
My co-author Keith Matthews has made available a set of slides he used when giving a recent presentation based on our submitted paper. These can be found at numbertheory.org/pdfs/dujella_slides.pdf
Jan
12
comment a family of Pellian equations
There are too many $k \in K$ to make verification practical for $k < 2^64$, but for the record we believe that $|K_1| = 3,040,378,747$ and $|K_2| = 1,725,632$.
Jan
12
comment a family of Pellian equations
For $k < 2^32$ we have $|K_1| = 48717, |K_2| = 1657, |K| = 50374$. These were all verified to be unique, so Andrej's conjecture is confirmed for $k < 2^32$, given that we accept that the enumeration process finds all $k$.
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12
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Jan
12
comment Greatest Prime Factors: For any prime p, is there an integer C such that for any x >= C, all but 1 integer in the sequence x+1, x+2, …, x+p has a greatest prime factor > p.
I'm kind of preoccupied with a couple of other questions, so I don't quite know what you mean by "patterns like A213523". This could just be attention-deficit on my part, but can you explain in more detail what you are looking for?
Jan
12
comment Consecutive integers with no large prime factors
You are absolutely right. Indeed, within Lehmer's paper, it's only in the title that an umlaut is used, within the text proper it's always "Størmer". Apologies to Wiki and anybody else I might have inadvertently offended! :-)
Jan
11
comment Greatest Prime Factors: For any prime p, is there an integer C such that for any x >= C, all but 1 integer in the sequence x+1, x+2, …, x+p has a greatest prime factor > p.
I meant $(pS_1, pS_1 + p)$. You can't edit comments!
Jan
11
comment Greatest Prime Factors: For any prime p, is there an integer C such that for any x >= C, all but 1 integer in the sequence x+1, x+2, …, x+p has a greatest prime factor > p.
Ah, but then again, we might still get lucky, for perhaps our $S_m$ is in fact always $(pS_1, pS_1 + p).
Jan
11
comment Greatest Prime Factors: For any prime p, is there an integer C such that for any x >= C, all but 1 integer in the sequence x+1, x+2, …, x+p has a greatest prime factor > p.
Correction: $S_2 < S_1$ was only true if $gcd(S, S+2)=1$. Clearly any $S, S+1$ will correspond to smooth pairs $(kS, kS + k)$ for any $k$ you like, so there is no avoiding the complications (wrt the Lehmer method) described above.
Jan
11
comment Uniqueness of values in recurrence relations
Aaron, that sounds like fun, is there anything I can do to contribute?
Jan
11
comment Uniqueness of values in recurrence relations
Thanks Todd! I'm very happy to be here :)
Jan
11
revised Greatest Prime Factors: For any prime p, is there an integer C such that for any x >= C, all but 1 integer in the sequence x+1, x+2, …, x+p has a greatest prime factor > p.
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11
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Jan
11
answered Greatest Prime Factors: For any prime p, is there an integer C such that for any x >= C, all but 1 integer in the sequence x+1, x+2, …, x+p has a greatest prime factor > p.
Jan
10
revised Consecutive integers with no large prime factors
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10
answered Consecutive integers with no large prime factors
Jan
10
comment Uniqueness of values in recurrence relations
And the second equation should of course read $mz^2 - (m-4)u^2 = 4$. For example, from $29 = U_2(5) = V_2(6)$ we obtain $7v^2 - 3u^2 = 5z^2 - u^2 = 4$ with $z=13, v=19, u=29$.
Jan
10
awarded  Commentator
Jan
10
comment Uniqueness of values in recurrence relations
Another problem is that you don't seem to be able to edit comments