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 A130177 #13 Feb 11 2024 09:16:44 %S A130177 0,11,263,59,23,101,109,1278886952463697,151,193,79,269,277,311,0,179, %T A130177 83,83003,479,487,181,563,571,613,1201,157,141509,739,773,479, %U A130177 6858037981,907,1291,983,227,6133,1109,1151,54331,1201,431,307,1327 %N A130177 For p = the n-th prime, a(n) = the least prime q greater than p+2 such that (p^2+q^2)/2 - 1 is a square, or a(n) = 0 if there is no such prime. %H A130177 Don Reble, <a href="/A130177/b130177.txt">Table of n, a(n) for n=1..787</a> %H A130177 Dean Hickerson, <a href="/A130177/a130177.txt">Proof that a(15) = 0</a> %H A130177 Number Theory Web, <a href="http://www.numbertheory.org/php/patz.html">Solving x^2-Dy^2=N</a> %H A130177 J. P. Robertson, <a href="https://web.archive.org/web/20180831180333/http://www.jpr2718.org/pell.pdf">Solving the Generalized Pell Equation</a> %e A130177 a(3) = 263 because (5^2+263^2)/2-1 = 186^2. %e A130177 a(4) = 59 because (7^2+59^2)/2-1 = 42^2. %e A130177 a(5) = 23 because (11^2+23^2)/2-1 = 18^2. %K A130177 nonn %O A130177 1,2 %A A130177 _Nick Hobson_, May 14 2007 %E A130177 Edited by _T. D. Noe_ and _Don Reble_, May 14 2007