This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A254929 #9 Feb 14 2015 23:50:48 %S A254929 3,7,5,11,7,15,13,9,17,23,13,11,27,19,17,25,23,35,19,17,25,39,23,31, %T A254929 21,19,25,41,33,19,29,51,37,27,49,55,41,31,47,29,23,37,45,35,51,43,63, %U A254929 31,25,67 %N A254929 Fundamental positive solution y = y2(n) of the second class of the Pell equation x^2 - 2*y^2 = A007522(n), n>=1 (primes congruent to 7 mod 8). %C A254929 The corresponding fundamental solution x2(n) of this second class of positive solutions is given in A254766(n). %C A254929 See the comments and the Nagell reference in A254764. %F A254929 A254766(n)^2 - 2*a(n)^2 = A007522(n) gives the second smallest positive (proper) solution of this (generalized) Pell equation. %F A254929 a(n) = 2*A254764(n) - 3*A254765(n), n >= 1. %e A254929 n = 2: 11^2 - 2*7^2 = 121 - 98 = 23. %e A254929 The smallest positive solution is (x1(2), y1(2)) = (5, 1) from (A254764(2), A254765(2)). %e A254929 See also A254766. %e A254929 a(4) = 2*7 - 3*1 = 11. %Y A254929 Cf. A007522, A254766, A254764,A254765, A254760, A254761, A254762, A254763. %K A254929 nonn,easy %O A254929 1,1 %A A254929 _Wolfdieter Lang_, Feb 11 2015