A191491 Diagonal sums of triangle A191490.

1, 1, 2, 3, 7, 14, 35, 86, 235, 660, 1968, 6078, 19570, 65129, 224057, 793794, 2892656, 10819274, 41480851, 162783153, 653115031, 2676107761, 11187573667, 47675621875, 206936072980, 914179405191, 4107584622566, 18759751255220, 87036191538839, 409986093418733

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..104

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[Sum[f[n - k, k], {k, 0, n}], {n, 0, 100}]

Prog

(Maxima) P[0]:1$
P[n]:=(1+(n-1)*q)*P[n-1]+q^n$
makelist(sum(coeff(expand(P[n-k]), q^k), k, 0, n), n, 0, 24);

Crossrefs

Cf. A191490.

Sequence in context: A180564 A113822 A036250 * A210345 A006660 A306844

Adjacent sequences: A191488 A191489 A191490 * A191492 A191493 A191494

Keyword

nonn

Author

Emanuele Munarini, Jun 03 2011

Status

approved