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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
OFFSET
0,3
LINKS
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
KEYWORD
nonn
AUTHOR
Emanuele Munarini, Jun 03 2011
STATUS
approved