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 A353213 #27 Feb 16 2025 08:34:03
%S A353213 1,3,7,18,52,208,1252,13598,288266,12293434,1031291298,166122463890,
%T A353213 50668153831842,29104823811067330,31455590793615376098,
%U A353213 64032471295321173271026,245999896624828253856990802,1787823725042236528801735181650,24639597076850046760911809226614418,645514762392876691902925550299969363858
%N A353213 Number of simple unlabeled non-null graphs on <= n nodes.
%C A353213 Also the number of (non-null) graph minors of the complete graph K_n.
%H A353213 Eric W. Weisstein, <a href="/A353213/b353213.txt">Table of n, a(n) for n = 1..87</a>
%H A353213 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GraphMinor.html">Graph Minor</a>
%H A353213 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SimpleGraph.html">Simple Graph</a>
%F A353213 a(n) = A006897(n) - 1.
%F A353213 a(n) = Sum_{k=1..n} A000088(k).
%Y A353213 Cf. A000088 (number of simple graphs on n nodes).
%Y A353213 Cf. A006897 (number of simple graphs on 0 to n nodes).
%K A353213 nonn
%O A353213 1,2
%A A353213 _Eric W. Weisstein_, Apr 30 2022