A353213 - OEIS

%I #27 Feb 16 2025 08:34:03

%S 1,3,7,18,52,208,1252,13598,288266,12293434,1031291298,166122463890,

%T 50668153831842,29104823811067330,31455590793615376098,

%U 64032471295321173271026,245999896624828253856990802,1787823725042236528801735181650,24639597076850046760911809226614418,645514762392876691902925550299969363858

%N Number of simple unlabeled non-null graphs on <= n nodes.

%C Also the number of (non-null) graph minors of the complete graph K_n.

%H Eric W. Weisstein, <a href="/A353213/b353213.txt">Table of n, a(n) for n = 1..87</a>

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GraphMinor.html">Graph Minor</a>

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SimpleGraph.html">Simple Graph</a>

%F a(n) = A006897(n) - 1.

%F a(n) = Sum_{k=1..n} A000088(k).

%Y Cf. A000088 (number of simple graphs on n nodes).

%Y Cf. A006897 (number of simple graphs on 0 to n nodes).

%K nonn

%O 1,2

%A _Eric W. Weisstein_, Apr 30 2022