Number of permutations of length n which avoid the patterns 1234, 2341, 4312.

Terms

a(0) =1a(1) =2a(2) =6a(3) =21a(4) =72a(5) =216a(6) =555a(7) =1252a(8) =2549a(9) =4787a(10) =8428a(11) =14079a(12) =22518a(13) =34722a(14) =51897a(15) =75510a(16) =107323a(17) =149429a(18) =204290a(19) =274777a(20) =364212a(21) =476412a(22) =615735a(23) =787128a(24) =996177a(25) =1249159a(26) =1553096a(27) =1915811a(28) =2345986a(29) =2853222