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A191491 Diagonal sums of triangle A191490. 2
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified May 27 20:17 EDT 2020. Contains 334667 sequences. (Running on oeis4.)