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 A329104 #18 Aug 28 2024 14:58:28 %S A329104 56,7192,7232,7912,10792,17272,30592,114256,2154584,3428368,89245784 %N A329104 Numbers m such that sigma(m) - tau(m) = 2m. %C A329104 Abundant numbers m with abundance A(m) = tau(m). %C A329104 Corresponding values of A(m) = tau(m): 8, 16, 14, 16, 16, 16, 16, 20, 32, 30, 32, ... %C A329104 a(12) > 10^13, if it exists. - _Giovanni Resta_, Nov 07 2019 %e A329104 Number 56 is in the sequence because sigma(56) - tau(56) = 2*56; 120 - 8 = 112. %t A329104 Select[Range[4*10^6], DivisorSigma[1, #] - DivisorSigma[0, #] == 2 # &] (* _Amiram Eldar_, Nov 04 2019 *) %o A329104 (Magma) [m: m in [1..10^5] | SumOfDivisors(m) - NumberOfDivisors(m) eq 2*m]; %o A329104 (PARI) isok(m) = my(f=factor(m)); sigma(f) - numdiv(f) == 2*m; \\ _Michel Marcus_, Nov 05 2019 %Y A329104 Cf. A000005, A000203, A033880, A065608. %Y A329104 Cf. A083874 (deficient numbers m with deficiency D(m) = tau(m)). %K A329104 nonn,more %O A329104 1,1 %A A329104 _Jaroslav Krizek_, Nov 04 2019 %E A329104 a(11) from _Amiram Eldar_, Nov 04 2019