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A163089
n! / (Product{k|n} k$). Here '$' denotes the swinging factorial function (A056040).
2
1, 1, 1, 1, 2, 4, 3, 36, 48, 96, 240, 14400, 2160, 518400, 90720, 141120, 1935360, 1625702400, 870912, 131681894400, 145152000, 15676416000, 287400960000, 1593350922240000, 14780620800, 7648084426752000, 1614043791360000
OFFSET
0,5
MAPLE
a := n -> n! / A163087(n):
MATHEMATICA
sf[n_] := With[{f = Floor[n/2]}, Pochhammer[f+1, n-f]/f!]; a[0] = 1; a[n_] := n!/Product[sf[k], {k, Divisors[n]}]; Table[a[n], {n, 0, 26}] (* Jean-François Alcover, Jul 26 2013 *)
CROSSREFS
Sequence in context: A071970 A182103 A303053 * A370635 A258371 A111172
KEYWORD
nonn
AUTHOR
Peter Luschny, Jul 21 2009
STATUS
approved