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 A027125 #7 Oct 23 2019 22:08:43 %S A027125 1,4,13,44,149,500,1660,5444,17640,56524,179322,563932,1759982, %T A027125 5456608,16821309,51600720,157615653,479664388,1455061181,4401607356, %U A027125 13282579293,39997017088,120215762283,360730451088,1080880047091 %N A027125 a(n) = A027113(n, 2n-7). %K A027125 nonn %O A027125 4,2 %A A027125 _Clark Kimberling_