A178845 Number of permutations of 2..n+1 with no element divisible by an adjacent element.

1, 2, 2, 12, 20, 180, 648, 5784, 36936, 485040, 2034876, 33492048, 373375392, 4974252864, 52465459392, 1067273994240, 11538658531008, 260749481442240

Offset

1,2

Links

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

Crossrefs

Sequence in context: A302368 A346757 A202669 * A140431 A092900 A303537

Adjacent sequences: A178842 A178843 A178844 * A178846 A178847 A178848

Keyword

nonn

Author

R. H. Hardin Jun 17 2010

Status

approved