login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 


Partial sums of A060648: sum of the inverse Moebius transform of the Dedekind psi function from 1 to n.
1

%I #14 Oct 10 2019 03:37:03

%S 1,5,10,20,27,47,56,78,95,123,136,186,201,237,272,318,337,405,426,496,

%T 541,593,618,728,765,825,878,968,999,1139,1172,1266,1331,1407,1470,

%U 1640,1679,1763,1838,1992,2035,2215,2260,2390,2509,2609,2658,2888,2953,3101

%N Partial sums of A060648: sum of the inverse Moebius transform of the Dedekind psi function from 1 to n.

%C 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.

%C 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))).

%H Vaclav Kotesovec, <a href="/A306775/b306775.txt">Table of n, a(n) for n = 1..10000</a>

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Dedekind_psi_function">Dedekind psi function</a>

%F a(n) ~ (5/4) * n^2.

%F a(n) = Sum_{k=1..n} A060648(k).

%F a(n) = Sum_{k=1..n} Sum_{d|k} A001615(d).

%F a(n) = Sum_{k=1..n} k * A064608(floor(n/k)).

%F a(n) = (1/2)*Sum_{k=1..n} 2^omega(k) * floor(n/k) * floor(1+n/k).

%F a(n) = Sum_{k=1..n} A001615(k)*floor(n/k). - _Ridouane Oudra_, Aug 27 2019

%p with(numtheory): psi := n -> n*mul(1+1/p, p in factorset(n)):

%p seq(add(psi(i)*floor(n/i), i=1..n), n=1..80); # _Ridouane Oudra_, Aug 27 2019

%t Accumulate[Table[Sum[EulerPhi[n/d] * DivisorSigma[0, d^2], {d, Divisors[n]}], {n, 1, 100}]] (* _Vaclav Kotesovec_, Oct 09 2019 *)

%o (PARI) a(n) = sum(k=1, n, 2^omega(k) * (n\k) * (1+n\k))/2;

%Y Cf. A001221, A001615, A034444, A060648, A061503, A064608.

%K nonn

%O 1,2

%A _Daniel Suteu_, Mar 09 2019

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 22 20:46 EDT 2024. Contains 376140 sequences. (Running on oeis4.)