Number of permutations of length n which avoid the patterns 1432, 2134, 2341.

Terms

a(0) =1a(1) =2a(2) =6a(3) =21a(4) =71a(5) =219a(6) =635a(7) =1776a(8) =4853a(9) =13068a(10) =34862a(11) =92438a(12) =244118a(13) =642947a(14) =1690256a(15) =4437947a(16) =11642149a(17) =30522573a(18) =79988157a(19) =209556918a(20) =548894043a(21) =1437513998a(22) =3764362904a(23) =9856889564a(24) =25808724004a(25) =67573730053a(26) =176920646370