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
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