Number of permutations of length n which avoid the patterns 1234, 1432, 3214.

Terms

a(0) =1a(1) =2a(2) =6a(3) =21a(4) =70a(5) =204a(6) =560a(7) =1617a(8) =4796a(9) =14249a(10) =41939a(11) =122658a(12) =358991a(13) =1053628a(14) =3095381a(15) =9089525a(16) =26674879a(17) =78271099a(18) =229705211a(19) =674214603a(20) =1978919196a(21) =5808153968a(22) =17046573229a(23) =50030848109a(24) =146839772058a(25) =430974323821