A191492 Central coefficients of triangle A191490.

1, 2, 18, 325, 9050, 342004, 16332659, 942562092, 63762184160, 4945947976997, 432648272729266, 42126940392610000, 4518312124929961241, 529235540464230162094, 67213443963719684144890, 9199173104526838608066833

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..45

Formula

a(n) = A191490(2*n,n).

Mathematica

f[n_, k_] := f[n, k] = f[n - 1, k] + (n - 1)f[n - 1, k - 1] + If[n == k, 1, 0]
f[_, 0] = 1;
f[0, _] = 0;
Table[f[2n, n], {n, 0, 100}]

Prog

(Maxima) P[0]:1$
P[n]:=(1+(n-1)*q)*P[n-1]+q^n$
makelist(coeff(expand(P[2*n]), q^n), n, 0, 12);

Crossrefs

Cf. A191490.

Sequence in context: A229490 A192985 A193264 * A090307 A123311 A349881

Adjacent sequences: A191489 A191490 A191491 * A191493 A191494 A191495

Keyword

nonn

Author

Emanuele Munarini, Jun 03 2011

Status

approved