A180897 Number of permutations of 9..n+8 with no element greater than or equal to the sum of its neighbors.

1, 0, 2, 6, 30, 180, 1260, 10080, 90720, 907200, 9797760, 114287040, 1416703680, 18712086480, 260499022680, 3833521421760, 59158317014280, 959784091498944

Offset

1,3

Links

Table of n, a(n) for n=1..18.

Crossrefs

Sequence in context: A180894 A180895 A180896 * A353184 A096769 A365975

Adjacent sequences: A180894 A180895 A180896 * A180898 A180899 A180900

Keyword

nonn

Author

R. H. Hardin, Sep 23 2010

Status

approved