Number of permutations of length n which avoid the patterns 2314, 3124, 4312.

Terms

a(0) =1a(1) =2a(2) =6a(3) =21a(4) =75a(5) =260a(6) =869a(7) =2817a(8) =8920a(9) =27745a(10) =85113a(11) =258256a(12) =776717a(13) =2319093a(14) =6882432a(15) =20321017a(16) =59738793a(17) =174960544a(18) =510756501a(19) =1486819229a(20) =4317417984a(21) =12509488161a(22) =36175413601a(23) =104433440896a(24) =301022300573a(25) =866485007957