Column 0 of triangle A129577.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =16a(5) =62a(6) =275a(7) =1350a(8) =7204a(9) =41345a(10) =253319a(11) =1647434a(12) =11318410a(13) =81820186a(14) =620213998a(15) =4915135856a(16) =40617213320a(17) =349192774319