A136686 Numbers k such that A136677(k) is prime.

19, 47, 164, 235, 504, 1109, 1112, 5134, 9222, 12803

Offset: 1

Author

Alexander Adamchuk, Jan 16 2008

Keywords

• nonn
• hard
• more

Comments

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

Links

• Eric Weisstein's World of Mathematics, Harmonic Number.

Crossrefs

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

Programs

Mathematica

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

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

a(10) from Michael S. Branicky, Nov 16 2024