Column 0 of triangle A128320.

Terms

a(0) =1a(1) =1a(2) =4a(3) =17a(4) =98a(5) =622a(6) =4512a(7) =35373a(8) =300974a(9) =2722070a(10) =26118056a(11) =263266346a(12) =2780054884a(13) =30586452652a(14) =349724463584