Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, up, up, down, down, down.

A177634

Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, up, up, down, down, down.

Terms

    a(0) =1a(1) =20a(2) =1680a(3) =369240a(4) =167472864a(5) =135960447600

External references