OFFSET
1,2
COMMENTS
For a guide to related sequences, see A210000.
MATHEMATICA
a = -n; b = n; z1 = 30;
t[n_] := t[n] = Flatten[Table[w*z - x*y, {w, a, b}, {x, a, b}, {y, a, b}, {z, a, b}]]
c[n_, k_] := c[n, k] = Count[t[n], k]
c1[n_, m_] := c1[n, m] = Sum[c[n, k], {k, -2*n^2, m}]
Table[c1[n, 2*n^2]-c1[n, 3n-1], {n, 1, z1}] (* A211153 *)
%/4 (* integers *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Apr 05 2012
STATUS
approved