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A136686 Numbers n such that A136677(n) is prime. 8
19, 47, 164, 235, 504, 1109, 1112, 5134, 9222 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A136677 = Numerator of Sum_{k=1..n} (-1)^(k+1)/k^6.

LINKS

Table of n, a(n) for n=1..9.

Eric Weisstein, The World of Mathematics: Harmonic Number

MATHEMATICA

Do[ f=Numerator[ Sum[ (-1)^(k+1)*1/k^6, {k, 1, n} ] ]; If[ PrimeQ[f], Print[ {n, f} ] ], {n, 1, 130} ]

CROSSREFS

Cf. A058313, A119682, A136675, A120296, A136676, A136677. Cf. A001008, A007406, A007408, A007410, A099828, A103345. Cf. A136681, A136682, A136683, A136684, A136685.

Sequence in context: A289728 A141973 A165672 * A130413 A156376 A063306

Adjacent sequences:  A136683 A136684 A136685 * A136687 A136688 A136689

KEYWORD

more,nonn,hard

AUTHOR

Alexander Adamchuk, Jan 16 2008

EXTENSIONS

a(4)-a(5) from Hiroaki Yamanouchi, Sep 22 2014

a(6) from Amiram Eldar, Mar 14 2019

a(7)-a(9) from Robert Price, Apr 20 2019

STATUS

approved

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Last modified June 2 11:35 EDT 2020. Contains 334771 sequences. (Running on oeis4.)