A221145 a(n) is the number of permutations of n elements with exactly one fixed point and no transpositions.

1, 0, 0, 8, 30, 144, 1120, 9120, 80892, 808640, 8908416, 106889760, 1389405160, 19452003648, 291782125440, 4668506495744, 79364583206160, 1428562661736960, 27142690917071872, 542853814698737280, 11399930105272855776, 250798462399704792320

Offset

1,4

Links

Table of n, a(n) for n=1..22.

Formula

Equals n*A038205(n-1). - Giovanni Resta, Nov 13 2012

Example

For n = 4 the a(4) = 8 solutions are (123), (124), (132), (134), (142), (143), (234), (243)

Crossrefs

Cf. A038205.

Sequence in context: A161222 A229374 A215471 * A098741 A027146 A302409

Adjacent sequences: A221142 A221143 A221144 * A221146 A221147 A221148

Keyword

nonn

Author

James Mahoney, Nov 13 2012

Extensions

Edited by N. J. A. Sloane, Jan 03 2013

Status

approved