%I A069996
%S A069996 1,12,81,432,2025,8748,35721,139968,531441,1968300,7144929,25509168,
%T A069996 89813529,312487308,1076168025,3673320192,12440502369,41841412812,
%U A069996 139858796529,464904586800,1537671920841,5062810950252,16600580533161
%N A069996 Number of spanning trees on the bipartite graph K_{3,n}.
%C A069996 With a leading zero, this is the second binomial transform of the octagonal 
               numbers A000567 and the binomial transform of A084857. - Paul Barry 
               (pbarry(AT)wit.ie), Jun 09 2003
%F A069996 a(n) = n^2 * 3^(n-1)
%F A069996 E.g.f.: exp(3x)(x+3x^2) - Paul Barry (pbarry(AT)wit.ie), Jul 23 2003
%t A069996 a[n_] := n^2*3^(n - 1); Table[ a[n], {n, 1, 24}]
%Y A069996 Sequence in context: A012195 A147650 A007010 this_sequence A163020 A164300 
               A175037
%Y A069996 Adjacent sequences: A069993 A069994 A069995 this_sequence A069997 A069998 
               A069999
%K A069996 nonn
%O A069996 1,2
%A A069996 Eric Weinhandl (eweinhandl(AT)msn.com), May 01 2002
%E A069996 Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), May 04 
               2002