A154654 Number of permutations of length n within distance 5.

1, 1, 2, 6, 24, 120, 720, 3720, 17304, 76110, 329462, 1441923, 6487445, 29555588, 135025756, 615260976, 2791161792, 12618600768, 57008446080, 257708989200, 1166042944564, 5279435858788, 23908888017477, 108262665958797, 490132089640318, 2218641353956314

Offset: 0

Author

Torleiv Kløve, Jan 13 2009

Keywords

• nonn
• easy

Comments

a(n) equals the permanent of the n X n matrix with 1's along the eleven central diagonals and 0's everywhere else. - John M. Campbell, Jul 10 2011

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..1000 (terms n=1..400 from R. H. Hardin)
• Torleiv Kløve, Spheres of Permutations under the Infinity Norm - Permutations with limited displacement, Reports in Informatics, Department of Informatics, University of Bergen, Norway, no. 376, November 2008.

Crossrefs

Cf. A000045, A002524, A002526, A072856.

Column k=5 of A306209.

Formula

G.f. is a rational function f(x)/g(x) where f has degree 132 and g has degree 142.

Extensions

a(0)=1 prepended by Alois P. Heinz, Jan 28 2019