This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A136685 #20 Feb 16 2025 08:33:07
%S A136685 2,19,51,78,84,130,294,910,2223,2642,3261,4312,4973,7846,9439
%N A136685 Numbers k such that A136676(k) is prime.
%C A136685 A136676(k) = Numerator of Sum_{j=1..k} (-1)^(j+1)/j^5.
%H A136685 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HarmonicNumber.html">Harmonic Number</a>
%t A136685 Do[ f=Numerator[ Sum[ (-1)^(k+1)*1/k^5, {k,1,n} ] ]; If[ PrimeQ[f], Print[ {n,f} ] ], {n,1,130} ]
%Y A136685 Cf. A058313, A119682, A136675, A120296, A136676, A136677.
%Y A136685 Cf. A001008, A007406, A007408, A007410, A099828, A103345.
%Y A136685 Cf. A136681, A136682, A136683, A136684, A136686.
%K A136685 nonn,more
%O A136685 1,1
%A A136685 _Alexander Adamchuk_, Jan 16 2008
%E A136685 a(7)-a(8) from _Amiram Eldar_, Mar 14 2019
%E A136685 a(9)-a(15) from _Robert Price_, Apr 16 2019