Number of permutations of length n which avoid the patterns 321 and 1324.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =13a(5) =32a(6) =72a(7) =148a(8) =281a(9) =499a(10) =838a(11) =1343a(12) =2069a(13) =3082a(14) =4460a(15) =6294a(16) =8689a(17) =11765a(18) =15658a(19) =20521a(20) =26525a(21) =33860a(22) =42736a(23) =53384a(24) =66057a(25) =81031a(26) =98606a(27) =119107a(28) =142885a(29) =170318