A074763 a(n) = (1/n) * Sum_{d divides n} (-1)^(n+d)*phi(n/d)*2^d.

2, 1, 4, 4, 8, 10, 20, 34, 60, 100, 188, 348, 632, 1162, 2192, 4114, 7712, 14542, 27596, 52480, 99880, 190558, 364724, 699248, 1342184, 2580796, 4971068, 9587560, 18512792, 35790376, 69273668, 134219794, 260301176, 505286416, 981706832

Offset: 1

Author

Vladeta Jovovic, Sep 06 2002

Keywords

• nonn

Crossrefs

Cf. A000010, A000031, A038063.

Formula

G.f.: Sum_{k>=1} phi(k)*log(1/(1 + 2*(-x)^k))/k. - Ilya Gutkovskiy, May 23 2019