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 A342926 #13 May 07 2021 01:12:42
%S A342926 -1,-1,1,-3,0,10,5,0,-8,11,5,20,-4,30,29,-15,4,-2,5,21,59,38,21,68,
%T A342926 -24,15,41,64,2,126,49,19,79,47,77,-16,-16,54,53,83,0,230,5,80,26,110,
%U A342926 65,80,-27,-16,105,25,28,190,101,188,119,65,33,272,-28,210,101,-63,59,318,5,97,203,314,85,47,-34,27,53,112,195
%N A342926 a(n) = A003415(sigma(n)) - n, where A003415 is the arithmetic derivative, and sigma is the sum of divisors of n.
%H A342926 Antti Karttunen, <a href="/A342926/b342926.txt">Table of n, a(n) for n = 1..10000</a>
%F A342926 a(n) = A342925(n) - n = A003415(A000203(n)) - n.
%t A342926 Array[If[#2 < 2, 0, #2 Total[#2/#1 & @@@ FactorInteger[#2]]] - #1 & @@ {#, DivisorSigma[1, #]} &, 77] (* _Michael De Vlieger_, Apr 08 2021 *)
%o A342926 (PARI)
%o A342926 A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
%o A342926 A342926(n) = (A003415(sigma(n))-n);
%Y A342926 Cf. A342925, A342924, A343223 [= gcd(A003415(n), a(n))].
%Y A342926 Cf. A342021 (positions of 0's), A343216 (of negative terms), A343217 (of nonnegative terms), A343218 (of positive terms).
%K A342926 sign
%O A342926 1,4
%A A342926 _Antti Karttunen_, Apr 08 2021