A321987 Number of permutations of n copies of 1..9 introduced in order 1..9 with no element equal to another within a distance of 1.

1, 12310199, 372419001449076, 16904301142107043464659, 967335448974819561548523580438, 64311863997340571475504065539218471107, 4749303210651587675797285013227098386984170468, 379065045836307787068046364731543393514652159389593652

Offset: 1

Author

Seiichi Manyama, Nov 23 2018

Keywords

• nonn

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..100

Crossrefs

Column k=9 of A322013.

Cf. A000012, A190917, A190918, A190920, A190923, A190927, A190932.

Formula

a(n) ~ 2187 * 2^(27*n-14) / (84035 * Pi^4 * n^4). - Vaclav Kotesovec, Nov 24 2018