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 A296244 #8 Aug 26 2021 09:47:28 %S A296244 15,21,35,39,45,51,55,63,69,75,77,85,87,91,93,95,105,111,115,117,119, %T A296244 123,133,135,141,143,147,153,155,159,165,175,183,187,189,195,203,207, %U A296244 213,215,219,221,225,231,235,237,245,247,253,255,259,261,267,273,275,279,285,287 %N A296244 Odd numbers k such that A007733(k) is even but 2^x == -1 (mod k) is insoluble. %Y A296244 Set difference of A296243 and A014657. %Y A296244 Cf. A002326, A007733. %K A296244 nonn %O A296244 1,1 %A A296244 _Max Alekseyev_, Dec 09 2017