A322179 The number of permutations of {1,2,...,n,1,2,...,n} with the property that there are k or more numbers between the two k's in the set for k=1,...,n.

1, 0, 0, 2, 40, 1070, 38936, 1896220, 119912476, 9587033840

Offset

0,4

Links

Table of n, a(n) for n=0..9.

Example

In case of n = 3.
  | permutation
--+-------------------
1 | [2, 3, 1, 2, 1, 3]
2 | [3, 1, 2, 1, 3, 2]

Crossrefs

Cf. A176127, A322180.

Sequence in context: A264713 A012637 A127429 * A012834 A304448 A012241

Adjacent sequences: A322176 A322177 A322178 * A322180 A322181 A322182

Keyword

nonn,more

Author

Seiichi Manyama, Nov 30 2018

Extensions

a(9) from Alois P. Heinz, Nov 30 2018

Status

approved