A127129 Column 2 of triangle A127126.

1, 3, 18, 139, 1314, 14658, 188012, 2721462, 43837014, 777266691, 15037898091, 315177210360, 7112634073455, 171930274269408, 4431595775955999, 121321383915646543, 3515347574087951331, 107474295428549047272

Offset: 2

Author

Paul D. Hanna, Jan 05 2007

Keywords

• nonn

Comments

Self-convolution cube of A127132.

Links

• G. C. Greubel, Table of n, a(n) for n = 2..80

Crossrefs

Cf. A127126; A127132; other columns: A127127, A127128, A127130.

Programs

Mathematica

T[n_, k_]:= T[n, k]= If[k==n, 1, Coefficient[(1 +x*Sum[x^(r-k-1)*Sum[T[r, c], {c,k+1,r}], {r,k+1,n}] + x^(n+1))^(k+1), x, n-k]]; Table[T[n, 2], {n, 2, 20}] (* G. C. Greubel, Jan 28 2020 *)