A170815 Number of permutations of 1..n with all differences of elements separated by distances 1 through 9 being respectively unique.

1, 2, 4, 12, 40, 116, 200, 444, 760, 2160, 4368, 7852, 12828, 17252, 19612, 21104, 18276, 15096, 10240, 6464, 3776, 2536

Offset

1,2

Comments

(Empirical) Equals A008404 for n<=2m+2, where m is the maximum difference separation 9.

Links

Table of n, a(n) for n=1..22.

Crossrefs

Sequence in context: A180487 A000940 A008404 * A170814 A170813 A170812

Adjacent sequences: A170812 A170813 A170814 * A170816 A170817 A170818

Keyword

nonn

Author

R. H. Hardin Dec 02 2009

Status

approved