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 A349439 #10 Nov 21 2021 01:19:30
%S A349439 2,0,0,1,0,2,0,1,1,4,0,-1,0,4,4,1,0,3,0,-2,4,8,0,-2,4,4,5,-2,0,-8,0,1,
%T A349439 8,8,8,-4,0,4,4,-4,0,-8,0,-4,10,8,0,-3,4,8,8,-2,0,2,16,-4,4,12,0,-6,0,
%U A349439 4,10,1,8,-16,0,-4,8,-16,0,-6,0,12,16,-2,16,-8,0,-6,19,8,0,-6,16,4,12,-8,0,-24,8,-4,4
%N A349439 a(n) = A349437(n) + A349438(n).
%H A349439 Antti Karttunen, <a href="/A349439/b349439.txt">Table of n, a(n) for n = 1..20000</a>
%H A349439 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%F A349439 a(1) = 2, and for n >1, a(n) = -Sum_{d|n, 1<d<n} A349437(d) * A349438(n/d). [As the sequences are Dirichlet inverses of each other]
%t A349439 f[p_, e_] := NextPrime[p, -1]^e; s[1] = 1; s[n_] := If[EvenQ[n], n/2, Times @@ f @@@ FactorInteger[n]]; sinv[1] = 1; sinv[n_] := sinv[n] = -DivisorSum[n, sinv[#] * s[n/#] &, # < n &]; a[n_] := DivisorSum[n, # * MoebiusMu[#] * s[n/#] + # * sinv[n/#] &]; Array[a, 100] (* _Amiram Eldar_, Nov 18 2021 *)
%o A349439 (PARI) A349439(n) = (A349437(n)+A349438(n)); \\ Needs also code from A349437 and A349438.
%Y A349439 Cf. A349437, A349438.
%K A349439 sign
%O A349439 1,1
%A A349439 _Antti Karttunen_, Nov 18 2021