A068087 a(n) = n^(2*n-2).

1, 4, 81, 4096, 390625, 60466176, 13841287201, 4398046511104, 1853020188851841, 1000000000000000000, 672749994932560009201, 552061438912436417593344, 542800770374370512771595361, 629983141281877223603213172736, 852226929923929274082183837890625

Offset

1,2

Comments

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).

Links

Table of n, a(n) for n=1..15.

Eric Weisstein's World of Mathematics, Complete Bipartite Graph

Eric Weisstein's World of Mathematics, Spanning Tree

Prog

(PARI) a(n)=n^(2*n-2) \\ Charles R Greathouse IV, Mar 31 2016

Crossrefs

a(n) = A000169(n)^2.

Cf. A069996, A001787, A072590, A294360.

Sequence in context: A268206 A337155 A268105 * A324088 A357513 A090599

Adjacent sequences: A068084 A068085 A068086 * A068088 A068089 A068090

Keyword

nonn,easy

Author

Sharon Sela (sharonsela(AT)hotmail.com), May 06 2002

Status

approved