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A028415 Numerator of Sum_{k=1..n} 1/phi(k). 6
1, 2, 5, 3, 13, 15, 47, 25, 13, 55, 281, 74, 301, 311, 637, 163, 1319, 453, 4117, 4207, 4267, 4339, 48089, 49079, 9895, 10027, 10115, 10247, 72125, 73511, 369403, 93217, 9391, 75821, 76283, 77207, 77515, 78131, 78593, 39643, 49727, 100609, 100939, 25408, 204419 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

REFERENCES

D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, Section I.27.

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Totient Summatory Function

EXAMPLE

1, 2, 5/2, 3, 13/4, 15/4, 47/12, 25/6, 13/3, 55/12, 281/60, 74/15, ...

MAPLE

map(numer, ListTools:-PartialSums(map(1/numtheory:-phi, [$1..10000]))); # Robert Israel, Apr 16 2019

MATHEMATICA

Numerator[Table[Sum[1/EulerPhi[k], {k, n}], {n, 50}]] (* Harvey P. Dale, Aug 24 2012 *)

CROSSREFS

Cf. A000010, A048049.

Sequence in context: A254790 A091265 A262373 * A211306 A267101 A035334

Adjacent sequences:  A028412 A028413 A028414 * A028416 A028417 A028418

KEYWORD

nonn,frac

AUTHOR

N. J. A. Sloane, Jun 28 2002

STATUS

approved

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Last modified August 10 02:28 EDT 2020. Contains 336367 sequences. (Running on oeis4.)