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 A356488 #11 Aug 11 2022 14:49:21 %S A356488 2,53,314,1042,1685,1825,3281,4586,5521,6770,8597,9050,11509,13858, %T A356488 17498,20369,24737,28085,28130,29041,31226,33226,37141,37585,42965, %U A356488 47402,49205,53954,57125,58913,66193,71674,79682,85685,94421,100946,110410,113290,115202 %N A356488 Numbers k such that the equation x^2 - k*y^4 = -1 has a solution for which |y| > 2. %C A356488 For k > 2, the equation x^2 - k*y^4 = -1 has at most one positive integer solution. If this solution (x, y) exists, we have v = y^2, where v is the smallest integer satisfying the Pell equation u^2 - k*v^2 = -1 (A130227). %H A356488 Chen Jian Hua and Paul Voutier, <a href="https://arxiv.org/abs/1401.5450">Complete solution of the diophantine equation X^2 + 1 = dY^4 and a related family of quartic Thue equations</a>, arXiv:1401.5450 [math.NT], 2014-2018. %e A356488 The equation x^2 - 2*y^4 = -1 has only two positive solutions (1, 1) and (239, 13), so 2 is in the sequence. %Y A356488 Cf. A031396, A130227, A182468. %K A356488 nonn %O A356488 1,1 %A A356488 _Jinyuan Wang_, Aug 09 2022