Number of permutations of length 3n with descent set {3, 6, ...} that avoid a certain pattern of length 4 or 5 (see Lewis, 2012, Appendix, for precise definition).

A217826

Number of permutations of length 3n with descent set {3, 6, ...} that avoid a certain pattern of length 4 or 5 (see Lewis, 2012, Appendix, for precise definition).

Terms

    a(0) =1a(1) =19a(2) =887a(3) =66816a(4) =6795966a(5) =850144907

External references