Number of permutations of length n which avoid the patterns 1342, 3241, 4312.

Terms

a(0) =1a(1) =2a(2) =6a(3) =21a(4) =73a(5) =241a(6) =759a(7) =2305a(8) =6806a(9) =19652a(10) =55725a(11) =155688a(12) =429719a(13) =1174344a(14) =3183298a(15) =8571979a(16) =22958381a(17) =61220351a(18) =162668347a(19) =430978487a(20) =1139179386a(21) =3005433282a(22) =7916965441a(23) =20829348046a(24) =54747238203a(25) =143781463846