OFFSET
0,2
COMMENTS
For a guide to related sequences, see A212959.
LINKS
Index entries for linear recurrences with constant coefficients, signature (3,-2,-2,3,-1).
FORMULA
a(n) = 3*a(n-1) - 2*a(n-2) - 2*a(n-3) + 3*a(n-4) - a(n-5).
G.f.: x*(4 + 5*x + 4*x^2 - x^3))/((1 - x)^4*(1 + x)).
a(n) = (n+1)^3 - A213398(n).
a(n) = (2*n*(2*n^2+4*n+1) - (-1)^n + 1)/4. - Bruno Berselli, Jul 02 2012
MATHEMATICA
t = Compile[{{n, _Integer}}, Module[{s = 0}, (Do[If[x != Min[Abs[w - x], Abs[x - y]], s = s + 1], {w, 0, n}, {x, 0, n}, {y, 0, n}]; s)]];
m = Map[t[#] &, Range[0, 60]]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jun 14 2012
STATUS
approved