OFFSET
1,1
COMMENTS
From D. Broadhurst, Oct 05 2011: (Start)
(p,q) is a Sophie Germain prime pair; (b,q) and (c,q) are Wieferich prime pairs; each of (b,c) is a square modulo q^2.
The sequence is now complete up to the 51st term, q=199065467.
It is a subsequence of A196511, where the latter does not require that q=2*p+1, is complete only up q=27370727, and contains q=2452757 and q=22796069, with q=4*p+1, (cf. link to post on "primenumbers" group), found by a simple analysis of Mossinghoff's results on Wieferich primes (cf. link).
With thanks to Mike Oakes. (End)
LINKS
D. J. Broadhurst, Table of n, a(n) for n = 1..51
D. J. Broadhurst et al., Re: Square factors of b^p-1 on yahoo group "primenumbers", Sept.-Oct. 2011
David Broadhurst and others, Square factors of b^p-1, digest of 81 messages in primenumbers Yahoo group, Sep 22 - Nov 29, 2011.
Michael Mossinghoff, Wieferich Prime Pairs, Barker Sequences, and Circulant Hadamard Matrices, as of Feb 12 2009.
CROSSREFS
KEYWORD
nonn
AUTHOR
M. F. Hasler, Oct 05 2011
STATUS
approved