A180882 Number of permutations p() of 1..n+5 with centered difference p(i+1)-p(i-1) < 0 exactly 4 times.

20, 525, 10010, 130914, 1438920, 13547688, 116189304, 917857512, 6866412696, 48911180175, 336896355510, 2249124467590, 14697484687600, 94059343340820, 593714385206800, 3693679623479664, 22778493196278456, 139016435228687562

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n=1..100

Prog

(bc) /* See A180887 */

Crossrefs

Column 5 of A180887.

Sequence in context: A250016 A371017 A337352 * A202920 A210486 A047682

Adjacent sequences: A180879 A180880 A180881 * A180883 A180884 A180885

Keyword

nonn

Author

R. H. Hardin, Sep 23 2010

Status

approved