Number of permutations of length n which avoid the patterns 1342, 2341, 4132; or avoid the patterns 2431, 3124, 4231.

A116742

Number of permutations of length n which avoid the patterns 1342, 2341, 4132; or avoid the patterns 2431, 3124, 4231.

Terms

    a(0) =1a(1) =2a(2) =6a(3) =21a(4) =75a(5) =261a(6) =877a(7) =2852a(8) =9020a(9) =27877a(10) =84533a(11) =252331a(12) =743389a(13) =2166062a(14) =6252642a(15) =17905365a(16) =50922495a(17) =143958513a(18) =404848717a(19) =1133309336a(20) =3159610856a(21) =8776920517a(22) =24301859561a(23) =67091484631a(24) =184734559165a(25) =507443649506

External references