Number of permutations of 3 copies of 1..n introduced in order 1..n with no element equal to another within a distance of 1.

A190826

Number of permutations of 3 copies of 1..n introduced in order 1..n with no element equal to another within a distance of 1.

Terms

    a(0) =1a(1) =0a(2) =1a(3) =29a(4) =1721a(5) =163386a(6) =22831355a(7) =4420321081

External references