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Dirichlet g.f.: Product_{k>=2} (1 - k^(-s))^4.
7

%I #5 Dec 14 2020 10:28:38

%S 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,

%T 12,8,4,-4,-20,-4,-4,12,12,12,-26,-4,12,12,-28,-4,-20,-4,4,4,12,-4,-8,

%U 2,4,12,4,-4,-28,12,-28,12,12,-4,-44,-4,12,4,-10,12,-20,-4,4,12,-20

%N Dirichlet g.f.: Product_{k>=2} (1 - k^(-s))^4.

%F a(1) = 1; a(n) = -Sum_{d|n, d < n} A339319(n/d) * a(d).

%F a(p^k) = A000727(k) for prime p.

%Y Cf. A000727, A114592, A339319, A339701, A339702, A339704, A339705, A339706, A339707.

%K sign

%O 1,2

%A _Ilya Gutkovskiy_, Dec 13 2020