A211437 Number of ordered triples (w,x,y) with all terms in {-n,...,0,...,n} and w*x*y=n.

1, 4, 12, 12, 24, 12, 36, 12, 40, 24, 36, 12, 72, 12, 36, 36, 60, 12, 72, 12, 72, 36, 36, 12, 120, 24, 36, 40, 72, 12, 108, 12, 84, 36, 36, 36, 144, 12, 36, 36, 120, 12, 108, 12, 72, 72, 36, 12, 180, 24, 72, 36, 72, 12, 120, 36, 120, 36, 36, 12, 216, 12, 36, 72

Offset: 0

Author

Clark Kimberling, Apr 12 2012

Keywords

• nonn

Comments

For a guide to related sequences, see A211422.

Crossrefs

Cf. A211422, A007425.

Programs

Mathematica

t[n_] := t[n] = Flatten[Table[w*x*y - n, {w, -n, n}, {x, -n, n}, {y, -n, n}]]
c[n_] := Count[t[n], 0]
t = Table[c[n], {n, 0, 80}]  (* A211437 *)
t/4                  (* A007425 for n>0 *)