Number of permutations of length n which avoid the patterns 4231 and 3124.

A165535

Number of permutations of length n which avoid the patterns 4231 and 3124.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =22a(5) =88a(6) =363a(7) =1508a(8) =6255a(9) =25842a(10) =106327a(11) =435965a(12) =1782733a(13) =7275351a(14) =29648647a(15) =120707058a(16) =491113791a(17) =1997372920a(18) =8121565606a(19) =33020039047a(20) =134248625367a(21) =545835561195

External references