Column 1 of triangle A107873; a(n) = C( n*(n+1)/2 + n+3, n).

A107875

Column 1 of triangle A107873; a(n) = C( n*(n+1)/2 + n+3, n).

Terms

    a(0) =1a(1) =5a(2) =28a(3) =220a(4) =2380a(5) =33649a(6) =593775a(7) =12620256a(8) =314457495a(9) =8996462475a(10) =290752384208

External references