OFFSET
1,4
COMMENTS
a(n) = 0 iff n is prime or 1.
EXAMPLE
For n = 4 the ordered triples are (1,2,2), (2,1,2), (2,2,1), (2,2,2), (2,2,3), (2,3,2), (3,2,2).
MATHEMATICA
Table[Dimensions[Solve[a*b*c == 0 && a != 0 && b != 0 && c != 0, {a, b, c}, Modulus -> n]][[1]], {n, 2, 100}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Luca Onnis, Mar 28 2022
STATUS
approved