Column 1 of triangular matrix A104446.

Terms

a(0) =1a(1) =2a(2) =5a(3) =13a(4) =39a(5) =139a(6) =587a(7) =2897a(8) =16462a(9) =106301a(10) =771313a(11) =6228073a(12) =55494336a(13) =541651873a(14) =5753940704a(15) =66147591142a(16) =818802488476