a(n) is the number of permutations of length n that avoid the pattern 321 and the mesh pattern (12, 307) or the same sequence for the mesh pattern (12, 409).
A289613
a(n) is the number of permutations of length n that avoid the pattern 321 and the mesh pattern (12, 307) or the same sequence for the mesh pattern (12, 409).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =8a(5) =31a(6) =116a(7) =407a(8) =1401a(9) =4825a(10) =16750a(11) =58730a(12) =207945a(13) =742821a(14) =2674348a(15) =9694739a(16) =35357549a(17) =129644653a(18) =477638546a(19) =1767263018a(20) =6564120229a(21) =24466266809a(22) =91482563408a(23) =343059613396
External references
- oeis: A289613