a(n) is the number of permutations of length n that avoid the pattern 231 and the mesh pattern (12, 409) or the same sequence for the mesh pattern (12, 473).
A289451
a(n) is the number of permutations of length n that avoid the pattern 231 and the mesh pattern (12, 409) or the same sequence for the mesh pattern (12, 473).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =2a(4) =8a(5) =32a(6) =117a(7) =408a(8) =1402a(9) =4826a(10) =16751a(11) =58731a(12) =207946a(13) =742822a(14) =2674349a(15) =9694740a(16) =35357550a(17) =129644654a(18) =477638547a(19) =1767263019a(20) =6564120230a(21) =24466266810a(22) =91482563409a(23) =343059613397
External references
- oeis: A289451