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A211177 Numerator of sum_{k=1..n}(-1)^k/phi(k) where phi=A000010 1
-1, 0, -1, 0, -1, 1, 1, 1, 1, 5, 19, 17, 29, 13, 21, 13, 47, 181, 503, 593, 533, 121, 1259, 1457, 6889, 7549, 7109, 7769, 52403, 59333, 11497, 6095, 29089, 61643, 59333, 63953, 62413, 7277, 21061, 2777 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,10

LINKS

Table of n, a(n) for n=1..40.

O. Bordelles, B. Cloitre, An Alternating Sum Involving the Reciprocal of Certain Multiplicative Functions, J. Int. Seq. 16 (2013) #13.6.3

FORMULA

a(n)/A211178(n)=c*log(n)+O(1) with a suitable constant c (see ref).

PROG

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

CROSSREFS

A211178 (denominators)

Sequence in context: A129734 A109325 A169698 * A260645 A226658 A212153

Adjacent sequences:  A211174 A211175 A211176 * A211178 A211179 A211180

KEYWORD

sign,frac

AUTHOR

Benoit Cloitre, Feb 01 2013

STATUS

approved

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Last modified October 22 19:03 EDT 2020. Contains 337953 sequences. (Running on oeis4.)