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 A027174 #7 Oct 24 2019 19:13:46 %S A027174 9,58,264,1106,4495,18014,71652,283760,1120806,4419928,17413572, %T A027174 68569666,269941451,1062631046,4183370636,16471711736,64870158866, %U A027174 255541666976,1006930883396,3968854010936,15648092510618,61714841143568 %N A027174 a(n) = A027170(2n, n-2). %K A027174 nonn %O A027174 2,1 %A A027174 _Clark Kimberling_