Antidiagonal triangle sequence based on recursion: f(n,a)=a*n*f(n-1,a)+f(n-2,a).

Terms

a(0) =0a(1) =0a(2) =1a(3) =0a(4) =1a(5) =2a(6) =0a(7) =1a(8) =4a(9) =7a(10) =0a(11) =1a(12) =6a(13) =25a(14) =30a(15) =0a(16) =1a(17) =8a(18) =55a(19) =204a(20) =157a(21) =0a(22) =1a(23) =10a(24) =97a(25) =666a(26) =2065a(27) =972a(28) =0a(29) =1