A289951 Number of permutations of [n] having exactly three nontrivial cycles.

15, 315, 4480, 56672, 703430, 8941790, 118685336, 1658897240, 24494859389, 382301179169, 6302039460704, 109568927676192, 2005758201911884, 38588518087076860, 778794884783432176, 16458419973887378416, 363578176719852275467, 8381709371219530604071

Offset

6,1

Comments

A nontrivial cycle has size > 1.

Links

Alois P. Heinz, Table of n, a(n) for n = 6..450

Wikipedia, Permutation

Formula

E.g.f.: (-log(1-x)-x)^3/3!*exp(x).

Mathematica

Drop [Range[0, 30]! CoefficientList[Series[(-Log[1 - x] - x)^3 / 3! Exp[x], {x, 0, 30}], x], 6] (* Vincenzo Librandi, Jul 22 2017 *)

Crossrefs

Column k=3 of A136394.

Sequence in context: A133766 A347980 A359404 * A112489 A062757 A088913

Adjacent sequences: A289948 A289949 A289950 * A289952 A289953 A289954

Keyword

nonn

Author

Alois P. Heinz, Jul 16 2017

Status

approved