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 A339718 #5 Dec 14 2020 16:00:51
%S A339718 1,-3,-3,3,-3,6,-3,-4,3,6,-3,-3,-3,6,6,9,-3,-3,-3,-3,6,6,-3,9,3,6,-4,
%T A339718 -3,-3,-3,-3,-12,6,6,6,3,-3,6,6,9,-3,-3,-3,-3,-3,6,-3,-18,3,-3,6,-3,
%U A339718 -3,9,6,9,6,6,-3,-3,-3,6,-3,15,6,-3,-3,-3,6,-3,-3,-15,-3,6,-3,-3,6,-3,-3,-18
%N A339718 Dirichlet g.f.: Product_{k>=2} 1 / (1 + k^(-s))^3.
%F A339718 a(1) = 1; a(n) = -Sum_{d|n, d < n} A339335(n/d) * a(d).
%F A339718 a(p^k) = A022598(k) for prime p.
%Y A339718 Cf. A022598, A316441, A339335, A339717, A339719, A339720, A339721, A339722.
%K A339718 sign
%O A339718 1,2
%A A339718 _Ilya Gutkovskiy_, Dec 14 2020