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A178845 Number of permutations of 2..n+1 with no element divisible by an adjacent element. 0
1, 2, 2, 12, 20, 180, 648, 5784, 36936, 485040, 2034876, 33492048, 373375392, 4974252864, 52465459392, 1067273994240, 11538658531008, 260749481442240 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..18.

CROSSREFS

Sequence in context: A054916 A194767 A202669 * A140431 A092900 A164961

Adjacent sequences:  A178842 A178843 A178844 * A178846 A178847 A178848

KEYWORD

nonn

AUTHOR

R. H. Hardin Jun 17 2010

STATUS

approved

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Last modified June 26 15:05 EDT 2017. Contains 288766 sequences.