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 A278581 #13 Dec 05 2016 08:38:47 %S A278581 1,2,3,4,5,6,7,8,9,10,12,13,16,18,25,36,49,50,169 %N A278581 Numbers n such that the Shimura subgroup Sigma(n) of the Jacobi variety J_0(n) has order 1. %D A278581 Ling, S., and J. Oesterlé. "The Shimura subgroup of J_0(N)." Astérisque, Vol. 196-197 (1991), 171-203. %Y A278581 Cf. A278582, A091401. %K A278581 nonn,fini,full %O A278581 1,2 %A A278581 _N. J. A. Sloane_, Nov 30 2016