A343394 - OEIS

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A343394

Sum of indices of n's distinct prime factors below n.

0, 0, 0, 1, 0, 3, 0, 1, 2, 4, 0, 3, 0, 5, 5, 1, 0, 3, 0, 4, 6, 6, 0, 3, 3, 7, 2, 5, 0, 6, 0, 1, 7, 8, 7, 3, 0, 9, 8, 4, 0, 7, 0, 6, 5, 10, 0, 3, 4, 4, 9, 7, 0, 3, 8, 5, 10, 11, 0, 6, 0, 12, 6, 1, 9, 8, 0, 8, 11, 8, 0, 3, 0, 13, 5, 9, 9, 9, 0, 4, 2, 14, 0, 7, 10, 15, 12, 6, 0, 6

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OFFSET

1,6

LINKS

Table of n, a(n) for n=1..90.

Index entries for sequences computed from indices in prime factorization

FORMULA

G.f.: Sum_{k>=1} k * x^(2*prime(k)) / (1 - x^prime(k)).

a(n) = 0 if n is prime, A066328(n) otherwise.

EXAMPLE

a(7) = a(prime(4)) = 0.

a(21) = a(3 * 7) = a(prime(2) * prime(4)) = 2 + 4 = 6.