OFFSET
0,2
FORMULA
a(n) = 14/9+2*n/3+4^(n+1)/9, n>0. [From R. J. Mathar, Jun 17 2009]
MATHEMATICA
CoefficientList[Series[(1-2x-5x^2+4x^3)/((1-4x)(1-x)^2), {x, 0, 30}], x] (* Harvey P. Dale, Jan 13 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 16 2009
STATUS
approved