OFFSET
0,3
COMMENTS
For a guide to related sequences, see A212959.
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,1,0,-1,-1,1).
FORMULA
a(n) = a(n-1)+a(n-2)-a(n-4)-a(n-5)+a(n-6).
G.f.: f(x)/g(x), where f(x) = 1 + x^2 + x^3 and g(x) = (1 + 2*x + 2*x^2 + x^3)*((1-x)^3).
MATHEMATICA
t = Compile[{{n, _Integer}}, Module[{s = 0}, (Do[If[2 w == 3 x + y, s = s + 1], {w, 0, n}, {x, 0, n}, {y, 0, n}]; s)]];
m = Map[t[#] &, Range[0, 70]] (* A212986 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jun 04 2012
STATUS
approved