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A292302 Expansion of (1 - x)*Sum_{k>=1} k*phi(k)*x^k/(1 - x^k), where phi() is the Euler totient function (A000010). 0

%I

%S 1,2,4,4,10,0,22,0,18,2,48,-34,80,-28,18,24,102,-90,160,-112,70,32,

%T 174,-206,220,-50,76,-74,340,-372,490,-248,94,42,84,-232,662,-304,70,

%U -196,738,-738,904,-586,60,240,642,-966,904,-538,348,-184,1030,-1116,690,-482,552,38,984,-1806

%N Expansion of (1 - x)*Sum_{k>=1} k*phi(k)*x^k/(1 - x^k), where phi() is the Euler totient function (A000010).

%C First differences of A057660.

%F G.f.: (1 - x)*Sum_{k>=1} k*phi(k)*x^k/(1 - x^k).

%t nmax = 60; Rest[CoefficientList[Series[(1 - x) Sum[EulerPhi[k] k x^k /(1 - x^k), {k, 1, nmax}], {x, 0, nmax}], x]]

%Y Cf. A057660, A174405.

%K sign

%O 1,2

%A _Ilya Gutkovskiy_, Sep 14 2017

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Last modified July 5 20:10 EDT 2020. Contains 335473 sequences. (Running on oeis4.)