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 A238091 #7 Mar 05 2020 02:59:25 %S A238091 1,4,9,18,31,33,39,56,58,94,96,103,156,239,245,253,255,257,275,277, %T A238091 420,610,788,790,792,1070,1665,1667,1669 %N A238091 A bisection of A136259. %F A238091 a(n) = A136259(2*n-1). - _Jinyuan Wang_, Mar 04 2020 %Y A238091 Cf. A136259, A238092. %K A238091 nonn,more %O A238091 1,2 %A A238091 _N. J. A. Sloane_, Feb 20 2014