a(n) is the number of permutations of length n that avoid the pattern 321 and the mesh pattern (12, 283) or the same sequence for the mesh pattern (12, 433).

A289614

a(n) is the number of permutations of length n that avoid the pattern 321 and the mesh pattern (12, 283) or the same sequence for the mesh pattern (12, 433).

Terms

    a(0) =1a(1) =1a(2) =1a(3) =2a(4) =9a(5) =34a(6) =122a(7) =417a(8) =1416a(9) =4846a(10) =16778a(11) =58766a(12) =207990a(13) =742876a(14) =2674414a(15) =9694817a(16) =35357640a(17) =129644758a(18) =477638666a(19) =1767263154a(20) =6564120382a(21) =24466266980a(22) =91482563598a(23) =343059613606

External references