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%I #8 Nov 09 2019 11:41:27
%S 1,1,21,2650,1452605,3149738046,26503552820514,868081172737564500,
%T 111606080497500509325405,56762846667123360827351083510,
%U 114847831981827229530824587617895286,927685362544629192461621864598358779955500,29976424929810726580224613882836823991388901138994
%N Number of labeled bipartite graphs on 2n vertices having equal parts and no isolated vertices.
%H Andrew Howroyd, <a href="/A122801/b122801.txt">Table of n, a(n) for n = 0..50</a>
%F For n>0, a(n) = A001700(n-1) * A048291(n) = A052332(2n) - A122802(2n).
%o (PARI) { A122801(n) = binomial(2*n-1,n) * sum(k=0, n, binomial(n, k) * (-1)^k * (2^(n-k)-1)^n ); }
%Y Cf. A122802, A048291, A052332, A001831, A002031, A047863, A001700.
%K nonn
%O 0,3
%A _Max Alekseyev_, Sep 11 2006
%E Terms a(11) and beyond from _Andrew Howroyd_, Nov 07 2019
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