The number of skew sum indecomposable permutations which avoid the patterns 3124 and 4312.

A228771

The number of skew sum indecomposable permutations which avoid the patterns 3124 and 4312.

Terms

    a(0) =1a(1) =1a(2) =3a(3) =12a(4) =53a(5) =234a(6) =1013a(7) =4306a(8) =18051a(9) =74903a(10) =308487a(11) =1263393a(12) =5152139a(13) =20941298a(14) =84897207a(15) =343467388a(16) =1387244237a(17) =5595368133a(18) =22543241377a(19) =90739796783a(20) =364954106877

External references