A127134 Central terms of triangle A127126; a(n) = A127126(2n,n).

1, 2, 18, 284, 6680, 211398, 8439235, 407247048, 23056215138, 1498169721930, 109876657252604, 8976437481923520, 808257688877060396, 79516093326076500590, 8485004019719253675540, 976009472808194554659440

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

Cf. A127126, A127127, A127128, A127129, A127130, A127131, A127132, A127133, A127135.

Sequence in context: A295183 A351768 A294193 * A131455 A084947 A123385

Adjacent sequences: A127131 A127132 A127133 * A127135 A127136 A127137

Keyword

nonn

Author

Paul D. Hanna, Jan 05 2007

Status

approved