OFFSET
1,1
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]
Table[c[n, 0], {n, 1, z1}] (* A209981 *)
c1[n_, m_] := c1[n, m] = Sum[c[n, k], {k, 1, m}]
t = Table[c1[n, 2*n^2], {n, 1, z1}] (* A211148 *)
2 t (* A211149 *)
t/8 (* integers *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Apr 04 2012
STATUS
approved