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A225964 Number of permutations of [n] having exactly 3 strong fixed blocks. 2
1, 9, 63, 419, 2868, 20932, 165662, 1432746, 13578086, 140951642, 1598792812, 19739303596, 264041415799, 3807692229035, 58907522237037, 973166134330293, 17094936849558000, 318092941562300736, 6248389843759774380, 129180041710223480596, 2803277432655658573548 (list; graph; refs; listen; history; text; internal format)
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

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Last modified February 8 15:16 EST 2023. Contains 360149 sequences. (Running on oeis4.)