Number of permutations of length n which avoid the patterns 1234, 1342, 4312.

Terms

a(0) =1a(1) =2a(2) =6a(3) =21a(4) =72a(5) =220a(6) =590a(7) =1409a(8) =3055a(9) =6118a(10) =11474a(11) =20373a(12) =34542a(13) =56304a(14) =88714a(15) =135713a(16) =202301a(17) =294730a(18) =420718a(19) =589685a(20) =813012a(21) =1104324a(22) =1479798a(23) =1958497a(24) =2562731a(25) =3318446a(26) =4255642a(27) =5408821a(28) =6817466a(29) =8526552