Number of permutations of [n] avoiding {2431, 1324, 1342}.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =21a(5) =77a(6) =285a(7) =1054a(8) =3889a(9) =14330a(10) =52800a(11) =194748a(12) =719602a(13) =2664989a(14) =9894443a(15) =36831886a(16) =137465657a(17) =514370974a(18) =1929432068a(19) =7254441076a(20) =27336758102a(21) =103229845714a(22) =390594944522