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A127135
Derived from the central terms (A127134) of triangle A127126; a(n) = A127126(2n,n)/(n+1).
6
1, 1, 6, 71, 1336, 35233, 1205605, 50905881, 2561801682, 149816972193, 9988787022964, 748036456826960, 62173668375158492, 5679720951862607185, 565666934647950245036, 61000592050512159666215
OFFSET
0,3
LINKS
FORMULA
a(n) = A127134(n)/(n+1).
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+1), {n, 0, 20}] (* G. C. Greubel, Jan 28 2020 *)
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jan 05 2007
STATUS
approved