Number of permutations of length n which avoid the patterns 1234, 1342, 4132.

Terms

a(0) =1a(1) =2a(2) =6a(3) =21a(4) =74a(5) =249a(6) =798a(7) =2459a(8) =7351a(9) =21457a(10) =61434a(11) =173120a(12) =481461a(13) =1324409a(14) =3610321a(15) =9768290a(16) =26267339a(17) =70277944a(18) =187252097a(19) =497243636a(20) =1316797076a(21) =3479358732a(22) =9176849481a(23) =24168624981a(24) =63576482894a(25) =167080909424