A115509 Number of circular permutations of {1, 2, ..., n} such that in every pair of adjacent elements each element in binary notation has ones at the same or adjacent positions to those of the other element.

1, 1, 2, 0, 0, 2, 4, 0, 0, 0, 0, 432, 1968, 24960, 161280, 0, 0, 0, 0, 0, 0, 0, 0, 24492908160, 314562424320, 6409032860160, 87275109519360, 546113470694400, 5633855851438080, 119328558793113600, 1461417642226483200, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset

1,3

Links

Table of n, a(n) for n=1..47.

Formula

If 2^(k+1) < = n < 3*2^k for k >= 1, then a(n) = 0.

Crossrefs

Cf. A115506, A115507, A115508.

Sequence in context: A147699 A250023 A151669 * A279360 A134312 A329790

Adjacent sequences: A115506 A115507 A115508 * A115510 A115511 A115512

Keyword

nonn

Author

Max Alekseyev, Jan 31 2006

Extensions

a(22)-a(47) from Max Alekseyev, Mar 19 2023

Status

approved