OFFSET
0,2
COMMENTS
a(n) is divisible by (n+1): a(n)/(n+1) = A127135(n).
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..50
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[2*n, n], {n, 0, 20}] (* G. C. Greubel, Jan 28 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jan 05 2007
STATUS
approved