OFFSET
0,2
LINKS
Colin Barker, Table of n, a(n) for n = 0..797
Index entries for linear recurrences with constant coefficients, signature (19,-19,1).
FORMULA
G.f.: x*(-13+x) / ( (x-1)*(x^2-18*x+1) ). - R. J. Mathar, Oct 26 2015
From Colin Barker, Mar 04 2016: (Start)
a(n) = (-3/4+1/40*(9+4*sqrt(5))^(-n)*(15-7*sqrt(5)+(9+4*sqrt(5))^(2*n)*(15+7*sqrt(5)))).
a(n) = 19*a(n-1) - 19*a(n-2) + a(n-3) for n>2. (End)
MATHEMATICA
LinearRecurrence[{19, -19, 1}, {0, 13, 246}, 20] (* Vincenzo Librandi, Mar 04 2016 *)
Table[(Fibonacci[6*n+4] - 3)/4, {n, 0, 30}] (* G. C. Greubel, Dec 02 2017 *)
PROG
(PARI) concat(0, Vec(x*(13-x)/((1-x)*(1-18*x+x^2)) + O(x^25))) \\ Colin Barker, Mar 04 2016
(PARI) for(n=0, 30, print1((fibonacci(6*n+4) - 3)/4, ", ")) \\ G. C. Greubel, Dec 02 2017
(Magma) [(Fibonacci(6*n+4) - 3)/4: n in [0..30]]; // G. C. Greubel, Dec 02 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved