Column 0 of triangle A107880.

Terms

a(0) =1a(1) =2a(2) =3a(3) =7a(4) =26a(5) =141a(6) =1034a(7) =9693a(8) =111522a(9) =1528112a(10) =24372513a(11) =444461496a(12) =9135985760a(13) =209223309377