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A255525 1/n! times the number of ordered pairs of permutation functions f,g on n elements where f(g(g(x))) = g(f(f(x))). 0
1, 1, 1, 1, 2, 3, 4, 6, 9, 13, 17, 27, 31, 42, 57, 83, 104 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

The fact that A239836(n) is a multiple of n! follows from a general result in group theory due to Solomon.

LINKS

Table of n, a(n) for n=0..16.

L. Solomon, The solutions of equations in groups, Arch. Math., V.20. no.3, (1969) 241-247.

FORMULA

a(n) = A239836(n)/n!.

CROSSREFS

Cf. A239836.

Sequence in context: A123648 A244393 A286929 * A129632 A016028 A239551

Adjacent sequences:  A255522 A255523 A255524 * A255526 A255527 A255528

KEYWORD

nonn,more

AUTHOR

Paul Boddington, Feb 24 2015

STATUS

approved

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Last modified July 21 21:14 EDT 2019. Contains 325199 sequences. (Running on oeis4.)