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 A138320 Numerators of the difference between the squarefree totient analogs of the harmonic numbers and the harmonic numbers: F_n-H_n. 4
 0, 1, 2, 5, 7, 4, 173, 587, 1481, 1859, 20701, 18391, 241393, 275713, 148367, 548423, 2342059, 241321, 41436061, 19263077, 40604659, 43779103, 1009564739, 1907583043, 9002492327, 9603126977, 27322095131, 25887926681, 752184042199 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS F_n-H_n approaches a constant, 'kappa', conjectured to be equivalent to the difference of B_3-gamma, where B_3 is Mertens' 3rd constant and gamma is Euler's constant. LINKS G. C. Greubel, Table of n, a(n) for n = 1..1000 FORMULA a(n) = Numerator[(Sum_{k=1..n} mu^2(k)/phi(k)) - H_n] where mu(k) is the Mobius function, phi(k) is Euler's Totient function and H_n is the n-th Harmonic Number. EXAMPLE Numerators of F_n - H_n, e.g. - F_1 - H_1 = (1/1-1/1), F_2 = ((1/1-1/1) + (1/1-1/2)),... F_11 = ((1/1-1/1) +(1/1-1/2) +(1/2-1/3) +(0-1/4) +(1/4-1/5) +(1/2-1/6) +(1/6-1/7) +(0-1/8) +(0-1/9) +(1/4-1/10) +(1/10-1/11)). MATHEMATICA Table[Numerator[Sum[MoebiusMu[k]^2/EulerPhi[k], {k, 1, n}]-HarmonicNumber[n]], {n, 1, 60}] PROG (PARI) for(n=1, 60, print1(numerator(sum(k=1, n, moebius(k)^2/eulerphi(k)) - sum(j=1, n, 1/j)), ", ")) \\ G. C. Greubel, Aug 31 2018 CROSSREFS Cf. A138312, A138313, A138312, A138316, A138317, A138321, A083343, A001620. Sequence in context: A296567 A205113 A098486 * A199275 A135007 A082880 Adjacent sequences:  A138317 A138318 A138319 * A138321 A138322 A138323 KEYWORD frac,nonn AUTHOR Dick Boland (abstract(AT)imathination.org), Mar 14 2008, Mar 27 2008 STATUS approved

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Last modified February 20 04:34 EST 2020. Contains 332063 sequences. (Running on oeis4.)