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 A348510 #12 Nov 24 2021 18:18:56
%S A348510 0,2,0,8,0,-4,0,24,18,10,0,6,0,-7,-10,64,0,18,0,0,0,0,0,-8,50,26,0,
%T A348510 -25,0,-20,0,32,-22,34,0,288,0,0,0,-8,0,-35,0,-22,0,-23,0,72,0,50,-34,
%U A348510 104,0,-36,0,0,0,58,0,-30,0,-31,126,384,0,-55,0,0,-46,-35,0,216,0,74,150,38,0,-52,0,320,324,82,0,-75
%N A348510 a(n) = A099377(n) - n, where A099377(n) is the numerator of the harmonic mean of the divisors of n.
%H A348510 Antti Karttunen, <a href="/A348510/b348510.txt">Table of n, a(n) for n = 1..20000</a>
%t A348510 a[n_] := Numerator[DivisorSigma[0, n]/DivisorSigma[-1, n]] - n; Array[a, 100] (* _Amiram Eldar_, Oct 31 2021 *)
%o A348510 (PARI)
%o A348510 A099377(n) = { my(d=divisors(n)); numerator(#d/sum(k=1, #d, 1/d[k])); }; \\ From A099377
%o A348510 A348510(n) = (A099377(n)-n);
%Y A348510 Cf. A099377, A250094 (positions of zeros), A348968, A348969.
%K A348510 sign
%O A348510 1,2
%A A348510 _Antti Karttunen_, Oct 31 2021