OFFSET
0,4
COMMENTS
For a guide to related sequences, see A211422.
FORMULA
Conjecture: a(n) = -(2*n + 5/3)*w(n) + w(n)^2 + (2/3)*w(n)^3 + (2*n + 5/6)*w(2*n) - (1/2)*w(2*n)^2 - (1/3)*w(2*n)^3, where w = A000196. - Velin Yanev, Nov 16 2021
MATHEMATICA
t[n_] := t[n] = Flatten[Table[w^2 - x - y, {w, 1, n}, {x, 1, n}, {y, 1, n}]]
c[n_] := Count[t[n], 0]
t = Table[c[n], {n, 0, 70}] (* A211516 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Apr 14 2012
STATUS
approved