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A339703
Dirichlet g.f.: Product_{k>=2} (1 - k^(-s))^4.
7
1, -4, -4, 2, -4, 12, -4, 8, 2, 12, -4, 4, -4, 12, 12, -5, -4, 4, -4, 4, 12, 12, -4, -28, 2, 12, 8, 4, -4, -20, -4, -4, 12, 12, 12, -26, -4, 12, 12, -28, -4, -20, -4, 4, 4, 12, -4, -8, 2, 4, 12, 4, -4, -28, 12, -28, 12, 12, -4, -44, -4, 12, 4, -10, 12, -20, -4, 4, 12, -20
OFFSET
1,2
FORMULA
a(1) = 1; a(n) = -Sum_{d|n, d < n} A339319(n/d) * a(d).
a(p^k) = A000727(k) for prime p.
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, Dec 13 2020
STATUS
approved