A217328 Number of self-inverse permutations in S_n with longest increasing subsequence of length 8.

1, 8, 71, 461, 3057, 18225, 109446, 628652, 3628517, 20538209, 116808172, 659078098, 3737763884, 21153403644, 120354760098, 685455514294, 3925104616303, 22535893275064, 130089736567064, 753604985013128, 4388755545268226, 25660332309744370, 150802834643569274

Offset

8,2

Comments

Also the number of Young tableaux with n cells and 8 rows.

Links

Alois P. Heinz, Table of n, a(n) for n = 8..400

Formula

a(n) = A182172(n,8)-A182172(n,7) = A007580(n)-A007578(n).

Example

a(8) = 1: 12345678.
a(9) = 8: 123456798, 123456879, 123457689, 123465789, 123546789, 124356789, 132456789, 213456789.

Crossrefs

Column k=8 of A047884.

Cf. A007578, A007580, A182172.

Sequence in context: A003364 A376053 A291892 * A193102 A038145 A198856

Adjacent sequences: A217325 A217326 A217327 * A217329 A217330 A217331

Keyword

nonn

Author

Alois P. Heinz, Sep 30 2012

Status

approved