A225964 Number of permutations of [n] having exactly 3 strong fixed blocks.

1, 9, 63, 419, 2868, 20932, 165662, 1432746, 13578086, 140951642, 1598792812, 19739303596, 264041415799, 3807692229035, 58907522237037, 973166134330293, 17094936849558000, 318092941562300736, 6248389843759774380, 129180041710223480596, 2803277432655658573548

Offset

7,2

Comments

See A186373 for the definition of strong fixed blocks.

Links

Alois P. Heinz, Table of n, a(n) for n = 7..450

Formula

a(n) ~ 2 * n! / n^5. - Vaclav Kotesovec, Aug 29 2014

Crossrefs

Column k=3 of A186373.

Sequence in context: A230547 A339786 A201885 * A037508 A037691 A206816

Adjacent sequences: A225961 A225962 A225963 * A225965 A225966 A225967

Keyword

nonn

Author

Alois P. Heinz, May 22 2013

Status

approved