login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A071708 Numerator of Sum_{k=1..n} phi(k)/k. 2
1, 3, 13, 8, 52, 19, 163, 361, 1223, 1307, 16477, 5749, 83977, 88267, 280817, 147916, 2754812, 2839897, 58552633, 60492571, 63263911, 65468386, 1612469468, 549883871, 579629587, 596790577, 1864736021, 1912541636, 58587007624, 59449633388, 1939984033478 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000

EXAMPLE

1, 3/2, 13/6, 8/3, 52/15, 19/5, 163/35, 361/70, 1223/210, ...

MAPLE

with(numtheory); seq(numer(add(phi(k)/k, k = 1..n)), n = 1..35); # G. C. Greubel, Aug 25 2019

MATHEMATICA

Table[Sum[EulerPhi[k]/k, {k, n}], {n, 35}]//Numerator (* G. C. Greubel, Aug 25 2019 *)

PROG

(PARI) a(n) = numerator(sum(k=1, n, eulerphi(k)/k));

vector(35, n, a(n)) \\ G. C. Greubel, Aug 25 2019

(MAGMA) [Numerator( &+[EulerPhi(k)/k: k in [1..n]] ): n in [1..35]]; // G. C. Greubel, Aug 25 2019

(Sage) [numerator( sum(euler_phi(k)/k for k in (1..n)) ) for n in (1..35)] # G. C. Greubel, Aug 25 2019

(GAP) List([1..35], n-> NumeratorRat( Sum([1..n], k-> Phi(k)/k) ) ); # G. C. Greubel, Aug 25 2019

CROSSREFS

Cf. A072155.

Sequence in context: A012789 A273025 A273122 * A136592 A085416 A107802

Adjacent sequences:  A071705 A071706 A071707 * A071709 A071710 A071711

KEYWORD

nonn,frac

AUTHOR

N. J. A. Sloane, Jun 28 2002

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 19 13:01 EDT 2019. Contains 328222 sequences. (Running on oeis4.)