Number of permutations p of 1,2,...,n satisfying p(i+5)-p(i)<>5 for all 1<=i<=n-5.

A189284

Number of permutations p of 1,2,...,n satisfying p(i+5)-p(i)<>5 for all 1<=i<=n-5.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =24a(5) =120a(6) =696a(7) =4572a(8) =34260a(9) =290328a(10) =2751480a(11) =28686024a(12) =328764732a(13) =4106158164a(14) =55495145304a(15) =806797105320

External references