OFFSET
0,1
REFERENCES
Z. Skupien, Sums of Powered Characteristic Roots Count Distance-Independent Circular Sets, Discussiones Mathematicae Graph Theory. Volume 33, Issue 1, Pages 217-229, ISSN (Print) 2083-5892, DOI: 10.7151/dmgt.1658, April 2013.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (2,0,-1,0,-1,1).
FORMULA
a(n) = A137726(n), for n>2 and a(0) = a(1) = a(2) = 3. [Bruno Berselli, Jun 17 2013]
MATHEMATICA
CoefficientList[Series[(3 - 2 x) / (1 - x - x^3) + x / (1 - x)^2 + x / (1 - x^2), {x, 0, 40}], x] (* Vincenzo Librandi, Jun 19 2013 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Jun 11 2013
STATUS
approved