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 A121095 #12 Feb 16 2023 19:08:58 %S A121095 0,0,1,4,14,47,164,565,1982,6977,24850,89082,321855,1169853,4276923, %T A121095 15713799,57998270,214934984,799473752,2983682702,11169374372, %U A121095 41929478873,157807392886,595340271682,2250901007539,8527699269192,32369066434276 %N A121095 Duplicate of A000908. %K A121095 dead %O A121095 0,4