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%I #10 Feb 08 2015 18:15:03
%S 0,4,64,1296,32768,1000000,35831808,1475789056,68719476736,
%T 3570467226624,204800000000000,12855002631049216,876488338465357824,
%U 64509974703297150976,5097655355238390956032,430467210000000000000000,38685626227668133590597632
%N (2n)^(n+1).
%p a:=n->mul(2*sum(1, j=2..n+1), k=1..n+1): seq(a(n), n=0..17); # _Zerinvary Lajos_, Jan 01 2009
%t Table[(2n)^(n+1),{n,0,20}] (* _Harvey P. Dale_, May 03 2011 *)
%K nonn
%O 0,2
%A _N. J. A. Sloane_, Jul 05 2003