Number of permutations of length n which avoid the patterns 2341, 3214, 4132.

Terms

a(0) =1a(1) =2a(2) =6a(3) =21a(4) =70a(5) =210a(6) =589a(7) =1592a(8) =4218a(9) =11069a(10) =28932a(11) =75528a(12) =197165a(13) =514920a(14) =1345484a(15) =3517427a(16) =9198984a(17) =24064848a(18) =62968211a(19) =164789078a(20) =431305300a(21) =1128953923a(22) =2955237882a(23) =7736173110a(24) =20252201791a(25) =53018445686a(26) =138799480530