OFFSET
1,3
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 1..40
FORMULA
log(a(n)) ~ n^2 * (log(n) + gamma - 3/2) / 2, where gamma is the Euler-Mascheroni constant A001620. - Vaclav Kotesovec, Feb 27 2021
EXAMPLE
a(4) = S(4,1)*S(4,2)*S(4,3)*S(4,4) = 1*7*6*1 = 42.
MAPLE
a:=n->mul(stirling2(n, k), k=1..n): seq(a(n), n=1..12); # Zerinvary Lajos, Jun 28 2007
MATHEMATICA
Table[Product[StirlingS2[n, k], {k, 1, n}], {n, 1, 12}] (* Vaclav Kotesovec, Feb 26 2021 *)
PROG
(PARI) a(n) = prod(k=1, n, stirling(n, k, 2)); \\ Michel Marcus, Dec 12 2015
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Leroy Quet, Jan 02 2001
STATUS
approved