Number of permutations of [n] avoiding {4231, 1243, 1234}.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =21a(5) =73a(6) =237a(7) =702a(8) =1881a(9) =4577a(10) =10216a(11) =21158a(12) =41097a(13) =75561a(14) =132523a(15) =223134a(16) =362589a(17) =571137a(18) =875246a(19) =1308934a(20) =1915277a(21) =2748105a(22) =3873897a(23) =5373886a(24) =7346385a(25) =9909345a(26) =13203156a(27) =17393702a(28) =22675681a(29) =29276201