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 A027124 #7 Oct 23 2019 21:57:13 %S A027124 1,2,7,24,81,270,886,2861,9109,28652,89211,275420,844320,2573161, %T A027124 7803656,23569375,70941900,212911167,637427166,1904416809,5679745126, %U A027124 16913962409,50304623519,149450737592,443593524167,1315613998440 %N A027124 a(n) = A027113(n, 2n-6). %K A027124 nonn %O A027124 3,2 %A A027124 _Clark Kimberling_