OFFSET
0,3
COMMENTS
Partial sums of A084183.
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (0,5,0,-4).
FORMULA
G.f.: x*(1+2*x+2*x^2) / ((1-x^2)*(1-4*x^2)). - typo fixed by Colin Barker, Sep 09 2016
From Colin Barker, Sep 09 2016: (Start)
a(n) = (5-(-1)^n)*(2^n-1)/6.
a(n) = 5*a(n-2) - 4*a(n-4) for n>3.
(End)
MAPLE
MATHEMATICA
LinearRecurrence[{0, 5, 0, -4}, {0, 1, 2, 7}, 40] (* Harvey P. Dale, Jan 18 2015 *)
PROG
(PARI) concat(0, Vec(x*(1+2*x+2*x^2)/((1-x^2)*(1-4*x^2)) + O(x^40))) \\ Colin Barker, Sep 09 2016
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, May 19 2003
STATUS
approved