A218463 - OEIS

%I #19 Feb 16 2025 08:33:18

%S 1,5,95,10297,11546911

%N Number of simple connected perfect matching graphs on 2n nodes.

%C Perfect matchings exist only for graphs with an even number of nodes.

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

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

%F a(n) = A218462(n) - A287652(n). - _Eric W. Weisstein_, May 29 2017

%F Inverse Euler transform of A218462. - _Andrew Howroyd_, Nov 03 2017

%Y Cf. A218462 (not-necessarily-connected simple perfect matching graphs).

%Y Cf. A287652 (disconnected simple perfect matching graphs).

%K nonn,more,changed

%O 1,2

%A _Eric W. Weisstein_, Mar 26 2013