A163088 (Product{k|n} k$) / n$. Here '$' denotes the swinging factorial function (A056040).

1, 1, 1, 1, 2, 1, 12, 1, 12, 6, 60, 1, 240, 1, 280, 180, 840, 1, 151200, 1, 90720, 840, 5544, 1, 15523200, 30, 24024, 3780, 5765760, 1, 93405312000, 1, 10810800, 16632, 437580, 4200, 6792641856000, 1, 1847560, 72072, 1173274502400

Offset: 0

Author

Peter Luschny, Jul 21 2009

Keywords

• nonn

Links

• Peter Luschny, Swinging Primes.

Crossrefs

Cf. A163087, A163089.

Programs

Maple

a := n -> A163087(n) / A056040(n):

Mathematica

sf[n_] := With[{f = Floor[n/2]}, Pochhammer[f+1, n-f]/f!]; a[0] = 1; a[n_] := Product[sf[k], {k, Divisors[n]}]/sf[n]; Table[a[n], {n, 0, 40}] (* Jean-François Alcover, Jul 26 2013 *)