a(n) is the number of permutations of length n that avoid the pattern 321 and the mesh pattern (12, 313) or the same sequence for the mesh pattern (12, 403).
A289608
a(n) is the number of permutations of length n that avoid the pattern 321 and the mesh pattern (12, 313) or the same sequence for the mesh pattern (12, 403).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =8a(5) =28a(6) =108a(7) =387a(8) =1354a(9) =4720a(10) =16524a(11) =58256a(12) =206968a(13) =740830a(14) =2670320a(15) =9686627a(16) =35341258a(17) =129611992a(18) =477573132a(19) =1767132084a(20) =6563858240a(21) =24465742694a(22) =91481515024a(23) =343057516456
External references
- oeis: A289608