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A292768
Partial sums of A065387.
2
2, 6, 12, 21, 31, 45, 59, 78, 97, 119, 141, 173, 199, 229, 261, 300, 334, 379, 417, 467, 511, 557, 603, 671, 722, 776, 834, 902, 960, 1040, 1102, 1181, 1249, 1319, 1391, 1494, 1568, 1646, 1726, 1832, 1914, 2022, 2108, 2212, 2314, 2408, 2502, 2642, 2741, 2854, 2958, 3080, 3186, 3324, 3436
OFFSET
1,1
LINKS
FORMULA
G.f.: (1/(1 - x))*Sum_{k>=1} (mu(k) + 1)*x^k/(1 - x^k)^2. - Ilya Gutkovskiy, Sep 28 2017
a(n) = (3/(Pi^2) + Pi^2/12) * n^2 + O(n*log(n)). - Amiram Eldar, Dec 03 2023
MATHEMATICA
Accumulate @ Table[EulerPhi[n] + DivisorSigma[1, n], {n, 100}] (* Amiram Eldar, Dec 03 2023 *)
PROG
(PARI) lista(nmax) = {my(f, s = 0); for(n = 1, nmax, f = factor(n); s += (sigma(f) + eulerphi(f)); print1(s, ", ")); } \\ Amiram Eldar, Dec 03 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 28 2017
STATUS
approved