A279046 a(n) = A000178(n) * Sum_{k=0..n} (-1)^k/k!.

1, 0, 1, 4, 108, 12672, 9158400, 46133452800, 1860226228224000, 675033837113180160000, 2449564623049780415692800000, 97778774486746890792389836800000000, 46836189690981206780971946461888512000000000, 291649927271171583734813938085106400257638400000000000

Offset

0,4

Links

Daniel Suteu, Table of n, a(n) for n = 0..19

Formula

a(n) ~ A000178(n) / e.

a(0) = 1, a(n) = n! * a(n-1) + (-1)^n * A000178(n-1).

Crossrefs

Cf. A000178.

Sequence in context: A107048 A269187 A185702 * A212803 A002109 A259373

Adjacent sequences: A279043 A279044 A279045 * A279047 A279048 A279049

Keyword

nonn,easy

Author

Daniel Suteu, Dec 04 2016

Status

approved