OFFSET
0,2
COMMENTS
For a guide to related sequences, see A211422.
MATHEMATICA
t[n_] := t[n] = Flatten[Table[3 w^2 + x*y, {w, -n, n}, {x, -n, n}, {y, -n, n}]]
c[n_] := Count[t[n], 0]
t = Table[c[n], {n, 0, 90}] (* A211427 *)
(t - 1)/4 (* integers *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Apr 10 2012
STATUS
approved