OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
FORMULA
G.f.: (2*z^2-4*z+1 - sqrt(12*z^2-8*z+1))/(2*z^4-8*z^3+4 z^2).
Conjecture: 2(n+2)*a(n) -4*(5n+4)*a(n-1) +3*(19n-2)*a(n-2) +4*(11-14n)*a(n-4) +12*(n-1)*a(n-4)=0. - R. J. Mathar, Dec 18 2011
a(n) ~ 18*6^(n+3/2)/(49*sqrt(Pi)*n^(3/2)). - Vaclav Kotesovec, Oct 24 2012
MATHEMATICA
CoefficientList[Series[(2*x^2-4*x+1-Sqrt[12*x^2-8*x+1])/(2*x^4-8*x^3+4*x^2), {x, 0, 20}], x] (* Vaclav Kotesovec, Oct 24 2012 *)
PROG
(PARI) z='z+O('z^50); Vec((2*z^2-4*z+1-sqrt(12*z^2-8*z+1))/(2*z^4-8*z^3+ 4*z^2)) \\ G. C. Greubel, Mar 29 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
José Luis Ramírez Ramírez, Dec 08 2011
STATUS
approved