Number of permutations of [n] avoiding {1324, 2431, 3241}.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =21a(5) =76a(6) =270a(7) =927a(8) =3074a(9) =9886a(10) =30985a(11) =95064a(12) =286558a(13) =851203a(14) =2497550a(15) =7252494a(16) =20874861a(17) =59630404a(18) =169225518a(19) =477513639a(20) =1340705306a(21) =3747697726a(22) =10435070737a(23) =28954040496a(24) =80087091646a(25) =220897122571a(26) =607726482470