OFFSET
0,2
LINKS
R. H. Hardin, Table of n, a(n) for n = 0..500
Index entries for linear recurrences with constant coefficients, signature (2,0,-2,2)
FORMULA
a(n) = 2*a(n-1) - 2*a(n-3) + 2*a(n-4). - Andrew Howroyd, Feb 14 2018
G.f.: (1 + 2*x^3)/(1 - 2*x + 2*x^3 - 2*x^4). - R. J. Mathar, Nov 30 2011
MATHEMATICA
LinearRecurrence[{2, 0, -2, 2}, {1, 2, 4, 8}, 50] (* G. C. Greubel, Sep 19 2017 *)
PROG
(PARI) Vec((1 + 2*x^3)/(1 - 2*x + 2*x^3 - 2*x^4) + O(x^40)) \\ G. C. Greubel, Sep 19 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 14 2009
EXTENSIONS
a(0)-a(3) prepended by Andrew Howroyd, Feb 14 2018
STATUS
approved