OFFSET
0,6
COMMENTS
For a guide to related sequences, see A212959.
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,1,0,0,-2,0,0,1,1,-1).
FORMULA
a(n) = a(n-1) + a(n-2) - 2*a(n-5) + a(n-8) + a(n-9) - a(n-10).
G.f.: (12*x^5 + 26*x^6 + 42*x^7 + 30*x^8 + 34*x^9)/(1 - x - x^2 + 2*x^5 - x^8 - x^9 + x^10).
a(n) = (n+1)^3 - A213491(n).
MATHEMATICA
t = Compile[{{n, _Integer}}, Module[{s = 0},
(Do[If[Length[Union[{w, x, y, Abs[w - x],
Abs[x - y]}]] == 5,
s = s + 1], {w, 0, n}, {x, 0, n}, {y, 0, n}]; s)]];
m = Map[t[#] &, Range[0, 60]] (* this sequence *)
LinearRecurrence[{1, 1, 0, 0, -2, 0, 0, 1, 1, -1}, {0, 0, 0, 0, 0, 12, 38, 92, 160, 286}, 60]
m/2 (* integers *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jun 13 2012
STATUS
approved