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 A076360 #19 Mar 16 2025 11:41:09
%S A076360 0,-1,0,-2,1,-1,1,-3,-2,-1,3,-6,1,1,1,-4,3,-8,3,-4,-1,2,5,-3,-2,1,1,
%T A076360 -4,5,-3,3,-6,3,1,3,-9,1,5,1,-3,5,-3,3,0,-4,5,7,-12,0,-8,5,-6,5,1,5,1,
%U A076360 3,5,9,-12,1,5,-4,-6,5,0,3,0,5,0,9,-20,1,1,-6,0,5,1,7,-10,-3,5,9,-16,5,5,9,3,9,-16,3,4,1,8,9,-10,3,-6,0,-9,5,1,5,1,-1
%N A076360 a(n) = d(sigma(n)) - sigma(d(n)), where d(n) is the number of divisors of n and sigma(n) is their sum.
%H A076360 Amiram Eldar, <a href="/A076360/b076360.txt">Table of n, a(n) for n = 1..10000</a>
%F A076360 a(n) = A000005(A000203(n)) - A000203(A000005(n)) = A062068(n) - A062069(n). - _Amiram Eldar_, Mar 16 2025
%t A076360 d0[x_] := DivisorSigma[0, x]
%t A076360 d1[x_] := DivisorSigma[1, x]
%t A076360 Table[ d0[d1[w]] - d1[d0[w]], {w, 1, 128}]
%o A076360 (PARI) a(n) = {my(f = factor(n)); numdiv(sigma(f)) - sigma(numdiv(f));} \\ _Amiram Eldar_, Mar 16 2025
%Y A076360 Cf. A000005, A000203, A062068, A062069.
%K A076360 easy,sign
%O A076360 1,4
%A A076360 _Labos Elemer_, Oct 08 2002