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

A228769

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

Terms

    a(0) =0a(1) =1a(2) =3a(3) =10a(4) =35a(5) =129a(6) =494a(7) =1935a(8) =7670a(9) =30582a(10) =122280a(11) =489552a(12) =1960956a(13) =7855994a(14) =31471731a(15) =126063782a(16) =504888839a(17) =2021777865a(18) =8094784697a(19) =32405289263a(20) =129709206465a(21) =519129580361

External references