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A306775
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Partial sums of A060648: sum of the inverse Moebius transform of the Dedekind psi function from 1 to n.
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1
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1, 5, 10, 20, 27, 47, 56, 78, 95, 123, 136, 186, 201, 237, 272, 318, 337, 405, 426, 496, 541, 593, 618, 728, 765, 825, 878, 968, 999, 1139, 1172, 1266, 1331, 1407, 1470, 1640, 1679, 1763, 1838, 1992, 2035, 2215, 2260, 2390, 2509, 2609, 2658, 2888, 2953, 3101
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OFFSET
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1,2
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COMMENTS
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In general, for m >= 1, Sum_{k=1..n} Sum_{d|k} psi_m(d) = Sum_{k=1..n} k^m * A064608(floor(n/k)), where psi_m(d) is the generalized Dedekind psi function.
Additionally, for m >= 1, Sum_{k=1..n} Sum_{d|k} psi_m(d) ~ (n^(m+1) * zeta(m+1)^2) / ((m+1) * zeta(2*(m+1))).
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LINKS
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FORMULA
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a(n) ~ (5/4) * n^2.
a(n) = Sum_{k=1..n} Sum_{d|k} A001615(d).
a(n) = Sum_{k=1..n} k * A064608(floor(n/k)).
a(n) = (1/2)*Sum_{k=1..n} 2^omega(k) * floor(n/k) * floor(1+n/k).
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MAPLE
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with(numtheory): psi := n -> n*mul(1+1/p, p in factorset(n)):
seq(add(psi(i)*floor(n/i), i=1..n), n=1..80); # Ridouane Oudra, Aug 27 2019
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MATHEMATICA
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Accumulate[Table[Sum[EulerPhi[n/d] * DivisorSigma[0, d^2], {d, Divisors[n]}], {n, 1, 100}]] (* Vaclav Kotesovec, Oct 09 2019 *)
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PROG
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(PARI) a(n) = sum(k=1, n, 2^omega(k) * (n\k) * (1+n\k))/2;
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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