Number of permutations of length n which avoid the patterns 1234, 1432, 4231.

Terms

a(0) =1a(1) =2a(2) =6a(3) =21a(4) =70a(5) =200a(6) =481a(7) =1004a(8) =1886a(9) =3270a(10) =5325a(11) =8246a(12) =12254a(13) =17596a(14) =24545a(15) =33400a(16) =44486a(17) =58154a(18) =74781a(19) =94770a(20) =118550a(21) =146576a(22) =179329a(23) =217316a(24) =261070a(25) =311150a(26) =368141a(27) =432654a(28) =505326a(29) =586820