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 A260993 #12 Aug 10 2015 00:07:32 %S A260993 22,23,26,28,29,30,31,33,35,37,39,40,41,43,46,47,48,50,53,59,61,65,71, %T A260993 79,83,89,101,131 %N A260993 Numbers n such that the modular curve X_0(n) contains infinitely many rational points of degree 2. %H A260993 Francesc Bars, <a href="http://dx.doi.org/10.1006/jnth.1998.2343">Bielliptic Modular Curves</a>, Journal of Number Theory, 76 (1999), 154-165. %Y A260993 Cf. A260990, A260991, A260992, A260994. %K A260993 nonn,fini,full %O A260993 1,1 %A A260993 _N. J. A. Sloane_, Aug 08 2015, following a suggestion from _Roger L. Bagula_, Jul 22 2015