The number of permutations avoiding simultaneously consecutive patterns 123 and 231.

A173938

The number of permutations avoiding simultaneously consecutive patterns 123 and 231.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =4a(4) =11a(5) =39a(6) =161a(7) =784a(8) =4368a(9) =27260a(10) =189540a(11) =1448860a(12) =12076408a(13) =109102564a(14) =1061259548a(15) =11060323280a(16) =122963473024

External references