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 A237610 #10 Jan 09 2015 08:02:02 %S A237610 8,15,20,23,24,32,47,60,71,72,80,87,92,95,96,116,128,135,152,159,167, %T A237610 180,188,191,200,207,212,215,216,239,240,263,276,284,288,303,311,320, %U A237610 335,344,348,359,368,375,380,383,384,392,404,423,431,447,456,464,479 %N A237610 Positive integers k such that x^2 - 10xy + y^2 + k = 0 has integer solutions. %e A237610 15 is in the sequence because x^2 - 10xy + y^2 + 15 = 0 has integer solutions, for example (x, y) = (2, 19). %o A237610 (PARI) is(n)=m=bnfisintnorm(bnfinit(x^2-10*x+1),-n);#m>0&&denominator(polcoeff(m[1],1))==1 \\ _Ralf Stephan_, Feb 11 2014 %Y A237610 Cf. A072256 (k = 8), A129445 (k = 15), A080806 (k = 20), A074061 (k = 23), A001079 (k = 24). %Y A237610 Cf. A031363, A084917, A237351, A237599, A237606, A237609. %K A237610 nonn %O A237610 1,1 %A A237610 _Colin Barker_, Feb 10 2014