Number of ordered set partitions of {1,...,n} into n-1 blocks avoiding the pattern 123.

A220101

Number of ordered set partitions of {1,...,n} into n-1 blocks avoiding the pattern 123.

Terms

    a(0) =0a(1) =1a(2) =6a(3) =27a(4) =112a(5) =450a(6) =1782a(7) =7007a(8) =27456a(9) =107406a(10) =419900a(11) =1641486a(12) =6418656a(13) =25110020a(14) =98285670a(15) =384942375a(16) =1508593920a(17) =5915896470a(18) =23213240820a(19) =91140287370a(20) =358042932000

External references