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 A045872 #7 Mar 08 2020 04:10:31 %S A045872 1,0,0,0,0,2,4,0,2,0,41,0,0,0,56,0,66,0 %N A045872 a(n) = A006792(n)/2. %K A045872 nonn %O A045872 10,6 %A A045872 _N. J. A. Sloane_