A292768 Partial sums of A065387.

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

N. J. A. Sloane, Table of n, a(n) for n = 1..10000

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

Cf. A000010, A000203, A065387.

Sequence in context: A214916 A323291 A161203 * A352990 A184637 A022450

Adjacent sequences: A292765 A292766 A292767 * A292769 A292770 A292771

Keyword

nonn

Author

N. J. A. Sloane, Sep 28 2017

Status

approved