%I A007681 M4632
%S A007681 1,9,50,294,1944,14520,121680,1134000,11652480,130999680,
%T A007681 1600300800,21115987200,299376000000,4539498163200,73316942899200,
%U A007681 1256675067648000,22784918188032000,435717099417600000
%N A007681 (2n+1)^2 n!.
%D A007681 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A007681 H. W. Gould, A class of binomial sums and a series transformation, Utilitas 
               Math., 45 (1994), 71-83.
%Y A007681 Sequence in context: A116169 A084367 A006974 this_sequence A115366 A002462 
               A034814
%Y A007681 Adjacent sequences: A007678 A007679 A007680 this_sequence A007682 A007683 
               A007684
%K A007681 nonn
%O A007681 0,2
%A A007681 N. J. A. Sloane (njas(AT)research.att.com).