A154656 Number of permutations of length n within distance 7.

1, 1, 2, 6, 24, 120, 720, 5040, 40320, 287280, 1865520, 11345160, 66349464, 381523758, 2193664790, 12764590275, 75796724309, 455383613924, 2750869551868, 16635586999056, 100439873614656, 604666567043712, 3629299734118656, 21736009354060800, 130082373922081536

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 central fifteen 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, A154654.

Column k=7 of A306209.

Extensions

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