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Product k^(2^(k-1)), k = 1..n.
(Formerly M3724)
1

%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_