OFFSET
0,2
COMMENTS
Every term is even.
For a guide to related sequences, see A212959.
LINKS
Index entries for linear recurrences with constant coefficients, signature (2,0,-1,-1,0,2,-1).
FORMULA
a(n) = 2*a(n-1) - a(n-3) - a(n-4) + 2*a(n-6) - a(n-7).
G.f.: (2*x*(2 + 5*x + 6*x^2 + 3*x^3 + 2*x^4))/((-1 + x)^4 (1 + x) (1 + x + x^2)).
a(n) = (n+1)^3 - A213495(n).
MATHEMATICA
t = Compile[{{n, _Integer}}, Module[{s = 0},
(Do[If[w != Min[Abs[w - x], Abs[x - y], Abs[y - w]], s = s + 1], {w, 0, n}, {x, 0, n}, {y, 0, n}]; s)]];
m = Map[t[#] &, Range[0, 60]] (* this sequence *)
m/2 (* integers *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jun 14 2012
STATUS
approved