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

A177585

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

Terms

    a(0) =1a(1) =6a(2) =90a(3) =2446a(4) =105516a(5) =6624618a(6) =570683441a(7) =64611629712

External references