Number of permutations of length n which avoid the patterns 1234, 2431, 4312.

Terms

a(0) =1a(1) =2a(2) =6a(3) =21a(4) =70a(5) =195a(6) =458a(7) =942a(8) =1752a(9) =3016a(10) =4886a(11) =7539a(12) =11178a(13) =16033a(14) =22362a(15) =30452a(16) =40620a(17) =53214a(18) =68614a(19) =87233a(20) =109518a(21) =135951a(22) =167050a(23) =203370a(24) =245504a(25) =294084a(26) =349782a(27) =413311a(28) =485426a(29) =566925