OFFSET
1,2
COMMENTS
For a guide to related sequences, see A210000.
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000
FORMULA
MATHEMATICA
a = 1; b = n; z1 = 35;
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]
u[n_] := u[n] = Sum[c[n, 2 k], {k, 0, n^2}]
v[n_] := v[n] = Sum[c[n, 2 k], {k, 1, n^2}]
w[n_] := w[n] = Sum[c[n, 2 k - 1], {k, 1, n^2}]
Table[u[n], {n, 1, z1}] (* A211066 *)
Table[v[n], {n, 1, z1}] (* A211067 *)
Table[w[n], {n, 1, z1}] (* A211068 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Mar 31 2012
STATUS
approved