A171844 Row sums of triangle A171843.

1, 4, 12, 31, 77, 188, 462, 1148, 2887, 7335, 18789, 48419, 125321, 325381, 846713, 2206891, 5758797, 15040102, 39304237, 102760572, 268757551, 703079117, 1839625401, 4814107671, 12599351527, 32977310272, 86319400527, 225954695164, 591492569038, 1548419254590

Offset: 1

Author

Gary W. Adamson, Dec 19 2009

Keywords

• nonn

Examples

			a(4) = 31 = (1 + 3 + 6 + 21) since row 4 of triangle A171843 = (1, 3, 6, 21).
		

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A171843.

Programs

PARI

seq(n)={Vec(sum(k=1, n, x^k*(1 - x^k)/((1 - x)*(1 - 2*x + x^2 - x^k)) + O(x*x^n)))} \\ Andrew Howroyd, Apr 13 2021

Formula

G.f.: Sum_{k>=1} x^k*(1 - x^k)/((1 - x)*(1 - 2*x + x^2 - x^k)). - Andrew Howroyd, Apr 13 2021

Extensions

a(10) and a(13) corrected and a(14) and beyond from Andrew Howroyd, Apr 13 2021