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%I #9 Sep 08 2022 08:45:06
%S 1,9,259,1063,136331,15259,5305837,21351973,1740485813,1745820149,
%T 2337022458319,2341131255319,5164765371583843,5173292359195843,
%U 5182536034853059,20760610355567611,102246457919648504843,3789825999242633809,26045507479622115279931,26064975970269506857723
%N Numerator of Sum_{k=1..n} phi(k)/k^3.
%H G. C. Greubel, <a href="/A072158/b072158.txt">Table of n, a(n) for n = 1..770</a>
%e 1, 9/8, 259/216, 1063/864, 136331/108000, 15259/12000, ...
%p with(numtheory); seq(numer(add(phi(k)/k^3, k = 1..n)), n = 1..25); # _G. C. Greubel_, Aug 26 2019
%t Numerator[Table[Sum[EulerPhi[k]/k^3,{k,n}],{n,20}]] (* _Harvey P. Dale_, May 27 2012 *)
%o (PARI) a(n) = numerator( sum(k=1, n, eulerphi(k)/k^3)); \\ _G. C. Greubel_, Aug 26 2019
%o (Magma) [Numerator( &+[EulerPhi(k)/k^3: k in [1..n]] ): n in [1..25]]; // _G. C. Greubel_, Aug 26 2019
%o (Sage) [numerator( sum(euler_phi(k)/k^3 for k in (1..n)) ) for n in (1..25)] # _G. C. Greubel_, Aug 26 2019
%o (GAP) List([1..25], n-> NumeratorRat( Sum([1..n], k-> Phi(k)/k^3) ) ); # _G. C. Greubel_, Aug 26 2019
%Y Cf. A072159.
%K nonn,frac
%O 1,2
%A _N. J. A. Sloane_, Jun 28 2002
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