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%I #13 Dec 27 2017 18:30:22
%S 1,4,81,4096,390625,60466176,13841287201,4398046511104,
%T 1853020188851841,1000000000000000000,672749994932560009201,
%U 552061438912436417593344,542800770374370512771595361,629983141281877223603213172736,852226929923929274082183837890625
%N a(n) = n^(2*n-2).
%C Number of spanning trees in the bipartite graph K(n,n). In general the number of spanning trees in the bipartite graph K(m,n) is m^(n-1) * n^(m-1).
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/CompleteBipartiteGraph.html">Complete Bipartite Graph</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/SpanningTree.html">Spanning Tree</a>
%o (PARI) a(n)=n^(2*n-2) \\ _Charles R Greathouse IV_, Mar 31 2016
%Y a(n) = A000169(n)^2.
%Y Cf. A069996, A001787, A072590, A294360.
%K nonn,easy
%O 1,2
%A Sharon Sela (sharonsela(AT)hotmail.com), May 06 2002
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