%I M3724 #21 Feb 18 2016 00:07:22
%S 1,4,324,21233664,3240000000000000000,
%T 25786061996226338865429872640000000000000000
%N Product k^(2^(k-1)), k = 1..n.
%D M. E. Mays, A worst case of the Fibonacci-Sylvester expansion, J. Combin. Math. Combin. Computing, 1 (1987), 141-148.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H Alois P. Heinz, <a href="/A005832/b005832.txt">Table of n, a(n) for n = 1..10</a>
%p a:= proc(n) a(n):= `if`(n=1, 1, a(n-1)*n^(2^(n-1))) end:
%p seq(a(n), n=1..7); # _Alois P. Heinz_, May 25 2013
%t Table[Product[k^(2^(k - 1)), {k, 1, n}], {n, 1, 10}] (* _Soumadeep Ghosh_, Feb 15 2016 *)
%o (PARI) a(n) = prod(k=1, n, k^(2^(k-1))) \\ _Michel Marcus_, May 25 2013
%K nonn,easy
%O 1,2
%A _N. J. A. Sloane_, _Jeffrey Shallit_