Number of permutations of length n which avoid the patterns 321, 1342, 1423.

Terms

a(0) =1a(1) =2a(2) =5a(3) =12a(4) =25a(5) =48a(6) =87a(7) =152a(8) =259a(9) =434a(10) =719a(11) =1182a(12) =1933a(13) =3150a(14) =5121a(15) =8312a(16) =13477a(17) =21836a(18) =35363a(19) =57252a(20) =92671a(21) =149982a(22) =242715a(23) =392762a(24) =635545a(25) =1028378a(26) =1663997a(27) =2692452a(28) =4356529a(29) =7049064