A136566 a(n) = sum of the exponents occurring only once each in the prime-factorization of n.

0, 1, 1, 2, 1, 0, 1, 3, 2, 0, 1, 3, 1, 0, 0, 4, 1, 3, 1, 3, 0, 0, 1, 4, 2, 0, 3, 3, 1, 0, 1, 5, 0, 0, 0, 0, 1, 0, 0, 4, 1, 0, 1, 3, 3, 0, 1, 5, 2, 3, 0, 3, 1, 4, 0, 4, 0, 0, 1, 2, 1, 0, 3, 6, 0, 0, 1, 3, 0, 0, 1, 5, 1, 0, 3, 3, 0, 0, 1, 5, 4, 0, 1, 2, 0, 0, 0, 4, 1, 2, 0, 3, 0, 0, 0, 6, 1, 3, 3, 0, 1, 0, 1, 4, 0