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 A254761 #10 Feb 18 2015 07:04:55 %S A254761 1,1,1,2,3,1,2,2,4,5,2,1,4,6,1,4,2,1,7,3,1,7,8,2,4,1,5,6,5,3,2,8,10,2, %T A254761 6,1,7,8,9,10,4,7,3,2,9,1,12,7,3,5 %N A254761 One half of the fundamental positive solution y = y1(n) of the first class of the Pell equation x^2 - 2*y^2 = A007519(n), n >= 1 (primes congruent to 1 mod 8). %C A254761 For the corresponding term x1(n) see A254760(n). %C A254761 See A254760 also for the Nagell reference. %C A254761 The least positive y solutions (that is the ones of the first class) for the primes +1 and -1 (mod 8) together (including in the first class also prime 2) are given in A002335. %F A254761 A254760(n)^2 - 2*(2*a(n))^2 = A007519(n) gives the smallest positive (proper) solution of this (generalized) Pell equation. %e A254761 See A254760. %e A254761 n = 3: 9^2 - 2*(2*1)^2 = 81 - 8 = 73. %Y A254761 Cf. A007519, A254760, A254762, 2*A254763, A002335. %K A254761 nonn,easy %O A254761 1,4 %A A254761 _Wolfdieter Lang_, Feb 12 2015