Number of permutations of [n] avoiding {4231, 1324, 2341}.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =21a(5) =73a(6) =239a(7) =736a(8) =2158a(9) =6102a(10) =16813a(11) =45493a(12) =121567a(13) =322108a(14) =848654a(15) =2227722a(16) =5834253a(17) =15258361a(18) =39874967a(19) =104169568a(20) =272109046a(21) =710846406a(22) =1857283957a(23) =4853664901a(24) =12686932951a(25) =33169384588a(26) =86737334054a(27) =226858067466a(28) =593434214373