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 A027118 #7 Oct 23 2019 20:33:19 %S A027118 1,2,3,7,16,39,98,252,659,1747,4682,12662,34505,94644,261069,723707, %T A027118 2014952,5631875,15796210,44444302,125405217,354765866,1006003375, %U A027118 2858939669,8141135778,23225997936,66376634429,190000938785 %N A027118 a(n) = A027113(n, 2n). %K A027118 nonn %O A027118 0,2 %A A027118 _Clark Kimberling_