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

Author

Karol A. Penson, Dec 10 2008

Keywords

• nonn
• easy
• changed

Programs

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 *)

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

Extensions

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