A127129 - OEIS

%I #10 Jan 28 2020 12:08:24

%S 1,3,18,139,1314,14658,188012,2721462,43837014,777266691,15037898091,

%T 315177210360,7112634073455,171930274269408,4431595775955999,

%U 121321383915646543,3515347574087951331,107474295428549047272

%N Column 2 of triangle A127126.

%C Self-convolution cube of A127132.

%H G. C. Greubel, <a href="/A127129/b127129.txt">Table of n, a(n) for n = 2..80</a>

%t 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 *)

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

%K nonn

%O 2,2

%A _Paul D. Hanna_, Jan 05 2007