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

A177593

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

Terms

    a(0) =1a(1) =6a(2) =90a(3) =2518a(4) =113052a(5) =7434180a(6) =673334112a(7) =80360724360

External references