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

0,5

Links

Table of n, a(n) for n=0..40.

Peter Luschny, Swinging Primes.

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 *)

Crossrefs

Cf. A163087, A163089.

Sequence in context: A069249 A128247 A161150 * A105608 A051190 A072512

Adjacent sequences: A163085 A163086 A163087 * A163089 A163090 A163091

Keyword

nonn

Author

Peter Luschny, Jul 21 2009

Status

approved