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A072158 Numerator of Sum_{k=1..n} phi(k)/k^3. 1
1, 9, 259, 1063, 136331, 15259, 5305837, 21351973, 1740485813, 1745820149, 2337022458319, 2341131255319, 5164765371583843, 5173292359195843, 5182536034853059, 20760610355567611, 102246457919648504843, 3789825999242633809, 26045507479622115279931, 26064975970269506857723 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..20.

EXAMPLE

1, 9/8, 259/216, 1063/864, 136331/108000, 15259/12000, ...

MATHEMATICA

Numerator[Table[Sum[EulerPhi[k]/k^3, {k, n}], {n, 20}]] (* Harvey P. Dale, May 27 2012 *)

CROSSREFS

Cf. A072159.

Sequence in context: A183424 A160073 A157575 * A001823 A229259 A117796

Adjacent sequences:  A072155 A072156 A072157 * A072159 A072160 A072161

KEYWORD

nonn,frac

AUTHOR

N. J. A. Sloane, Jun 28 2002

STATUS

approved

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Last modified January 17 14:12 EST 2019. Contains 319225 sequences. (Running on oeis4.)