Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, up, down, up, up, up.

A177592

Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, up, down, up, up, up.

Terms

    a(0) =1a(1) =6a(2) =90a(3) =2512a(4) =112440a(5) =7367330a(6) =664573798a(7) =78969593280

External references