Column 1 of triangle A107880.

Terms

a(0) =1a(1) =2a(2) =5a(3) =19a(4) =104a(5) =766a(6) =7197a(7) =82910a(8) =1136923a(9) =18141867a(10) =330940109a(11) =6803936050a(12) =155839142185