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 A162109 #8 Sep 05 2025 14:15:32 %S A162109 2,4,9,56,499,8000,207554,9382078,732814910,101599273769, %T A162109 25151730678684,11252735518379960,9169484084583765409, %U A162109 13716523699765295956974,37907229783585348802398136,194640906178869631364050052914 %N A162109 Number of n X n symmetric binary arrays with rows, considered as graycode numbers, in strictly increasing order. %K A162109 nonn,changed %O A162109 1,1 %A A162109 _R. H. Hardin_, Jun 25 2009