A180166 Row sums of triangle A180165.

1, 3, 7, 18, 51, 161, 560, 2123, 8691, 38142, 178407, 885041, 4636948, 25564727, 147848651, 894448186, 5646589363, 37115577265, 253517232120, 1796241061843, 13180234725987, 100009217354694, 783656713398383, 6333420109604593, 52732283687195340, 451831859926030943

Offset

1,2

Links

Andrew Howroyd, Table of n, a(n) for n = 1..500

Formula

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

Example

a(5) = 151 = sum of row 5 terms of triangle A180165: (1 + 5 + 15 + 22 + 8).

Prog

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

Crossrefs

Row sums of A180165.

Sequence in context: A103177 A262784 A202261 * A369842 A256873 A353213

Adjacent sequences: A180163 A180164 A180165 * A180167 A180168 A180169

Keyword

nonn

Author

Gary W. Adamson, Aug 14 2010

Extensions

a(8) and a(11) corrected and a(14) and beyond from Andrew Howroyd, Apr 13 2021

Status

approved