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 A339720 #5 Dec 14 2020 16:01:02
%S A339720 1,-5,-5,10,-5,20,-5,-15,10,20,-5,-30,-5,20,20,30,-5,-30,-5,-30,20,20,
%T A339720 -5,45,10,20,-15,-30,-5,-55,-5,-56,20,20,20,35,-5,20,20,45,-5,-55,-5,
%U A339720 -30,-30,20,-5,-105,10,-30,20,-30,-5,45,20,45,20,20,-5,45,-5,20,-30,85,20
%N A339720 Dirichlet g.f.: Product_{k>=2} 1 / (1 + k^(-s))^5.
%F A339720 a(1) = 1; a(n) = -Sum_{d|n, d < n} A339337(n/d) * a(d).
%F A339720 a(p^k) = A022600(k) for prime p.
%Y A339720 Cf. A022600, A316441, A339337, A339717, A339718, A339719, A339721, A339722.
%K A339720 sign
%O A339720 1,2
%A A339720 _Ilya Gutkovskiy_, Dec 14 2020