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 A318367 a(n) = Sum_{d|n} (-1)^(n/d+1)*d*prime(d). 0
 2, 4, 17, 20, 57, 67, 121, 116, 224, 239, 343, 371, 535, 487, 777, 660, 1005, 958, 1275, 1095, 1669, 1401, 1911, 1715, 2482, 2097, 3005, 2295, 3163, 2987, 3939, 3156, 4879, 3727, 5391, 4502, 5811, 4925, 7063, 5271, 7341, 6619, 8215, 6433, 9849, 7249, 9919, 8691, 11244, 9264 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS FORMULA G.f.: Sum_{k>=1} k*prime(k)*x^k/(1 + x^k). L.g.f.: log(Product_{k>=1} (1 + x^k)^prime(k)) = Sum_{n>=1} a(n)*x^n/n. MATHEMATICA Table[Sum[(-1)^(n/d + 1) d Prime[d], {d, Divisors[n]}], {n, 50}] nmax = 50; Rest[CoefficientList[Series[Sum[k Prime[k] x^k/(1 + x^k), {k, 1, nmax}], {x, 0, nmax}], x]] nmax = 50; Rest[CoefficientList[Series[Log[Product[(1 + x^k)^Prime[k], {k, 1, nmax}]], {x, 0, nmax}], x] Range[0, nmax]] PROG (PARI) a(n) = sumdiv(n, d, (-1)^(n/d+1)*d*prime(d)); \\ Michel Marcus, Aug 25 2018 CROSSREFS Cf. A033286, A061150, A061151, A061152. Sequence in context: A254206 A118242 A006276 * A317488 A103051 A095018 Adjacent sequences:  A318364 A318365 A318366 * A318368 A318369 A318370 KEYWORD nonn AUTHOR Ilya Gutkovskiy, Aug 24 2018 STATUS approved

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Last modified September 26 11:06 EDT 2020. Contains 337353 sequences. (Running on oeis4.)