OFFSET
0,4
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (5,-5,-3).
FORMULA
a(n) = A193519(n)/2.
From R. J. Mathar, Mar 17 2008: (Start)
O.g.f.: x^2/((1-3*x)*(1-2*x-x^2)).
a(n) = (3^n - A078057(n))/2 . (End)
a(n) = (1/4)*(2*3^n - A002203(n+1)). - G. C. Greubel, Jan 05 2022
MATHEMATICA
LinearRecurrence[{5, -5, -3}, {0, 0, 1}, 30] (* Harvey P. Dale, Nov 28 2013 *)
PROG
(Magma) [n le 3 select Floor((n-1)/2) else 5*Self(n-1) -5*Self(n-2) -3*Self(n-3): n in [1..31]]; // G. C. Greubel, Jan 05 2022
(Sage) [(2*3^n - lucas_number2(n+1, 2, -1))/4 for n in (0..30)] # G. C. Greubel, Jan 05 2022
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paul Curtz, Mar 06 2008
STATUS
approved