A152653 a(n) = (n-1)! * Product_{k=1..n-2} (n-k)!.

1, 1, 4, 72, 6912, 4147200, 17915904000, 632073093120000, 203881496916787200000, 665860658410473652224000000, 24162751572399267891904512000000000, 10609496941616618062463314270617600000000000

Offset

1,3

Links

Table of n, a(n) for n=1..12.

Formula

G.f.: G(0)/2, where G(k)= 1 + 1/(1 - 1/(1 + 1/((k+2)!-(k+1)!)/x/G(k+1))); (continued fraction). - Sergei N. Gladkovskii, Jun 14 2013

a(n) = A000178(n)/n. - Vaclav Kotesovec, Jun 28 2013

a(n) = Det_{i,j = 1..n} i^(j+1), n >= 1, (alternants). - Wolfdieter Lang, Oct 10 2015

Mathematica

Table[(n-1)!Product[(n-k)!, {k, n-2}], {n, 13}] (* Harvey P. Dale, Jul 26 2011 *)
Table[(n-1)! BarnesG[n+1], {n, 1, 12}] (* Jean-François Alcover, Nov 07 2016 *)

Crossrefs

Sequence in context: A177392 A158269 A024257 * A344693 A172478 A087315

Adjacent sequences: A152650 A152651 A152652 * A152654 A152655 A152656

Keyword

nonn,easy

Author

Karol A. Penson, Dec 10 2008

Extensions

a(12) provided by Harvey P. Dale, Jul 26 2011

Status

approved