OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Shalosh B. Ekhad and Doron Zeilberger, Automatic Solution of Richard Stanley's Amer. Math. Monthly Problem #11610 and ANY Problem of That Type, arXiv:1112.6207, 2011. See subpages for rigorous derivations of g.f., recurrence, asymptotics for this sequence.
FORMULA
G.f.: 1/((1 - 2*x)*sqrt(1 - 2*x - 3*x^2)). - G. C. Greubel, Mar 03 2017
MAPLE
series(1/((1-2*x)*sqrt(1-2*x-3*x^2)), x=0, 31); # Mark van Hoeij, May 10 2013
MATHEMATICA
CoefficientList[Series[1/((1 - 2*x)*Sqrt[1 - 2*x - 3*x^2]), {x, 0, 50}], x] (* G. C. Greubel, Mar 03 2017 *)
PROG
(PARI) x='x+O('x^66); Vec(1/((1-2*x)*sqrt(1-2*x-3*x^2))) \\ Joerg Arndt, May 11 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Apr 07 2012
STATUS
approved