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).
A217824
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) =642a(3) =27453a(4) =1339531a(5) =71173264
External references
- oeis: A217824