OFFSET
1,1
LINKS
FORMULA
From Zak Seidov, Apr 22 2009: (Start)
a(n) = a(n-2) + 3.
a(n) = (1/4)*(6*n + 9 - 13*(-1)^n). (End)
From R. J. Mathar, Apr 22 2009: (Start)
a(n) = a(n-1) + a(n-2) - a(n-3) = 3*n/2 + 9/4 + 13*(-1)^(n+1)/4.
G.f.: x*(7-5*x+x^2)/((1+x)*(x-1)^2). (End)
MATHEMATICA
LinearRecurrence[{1, 1, -1}, {7, 2, 10}, 80] (* Harvey P. Dale, Jan 16 2015 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Apr 21 2009
EXTENSIONS
More terms from Zak Seidov and R. J. Mathar, Apr 22 2009
STATUS
approved