Number of permutations of [n] avoiding {4231, 2134, 1243}.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =21a(5) =70a(6) =205a(7) =536a(8) =1264a(9) =2722a(10) =5424a(11) =10122a(12) =17871a(13) =30102a(14) =48703a(15) =76108a(16) =115394a(17) =170386a(18) =245770a(19) =347214a(20) =481497a(21) =656646a(22) =882081a(23) =1168768a(24) =1529380a(25) =1978466a(26) =2532628a(27) =3210706a(28) =4033971a(29) =5026326