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 A328951 #28 Jul 25 2023 09:14:40 %S A328951 60,5472,2500704,24361213461200 %N A328951 Numbers m such that sigma(m) + tau(m) = 3m. %C A328951 Abundant numbers m with abundance A(m) = m - tau(m) = A049820(m), where A049820(n) is the number of non-divisors of n. %C A328951 Subsequence of A056076. %C A328951 Corresponding values of A(m) = m - tau(m): 48, 5436, 2500632, ... %C A328951 4 is the only number m with deficiency D(m) = m - tau(m). %C A328951 808989640739424 is also a term. - _Giovanni Resta_, Nov 14 2019 %e A328951 60 is a term because sigma(60) + tau(60) = 3*60; 168 + 12 = 180 = 3*60. %t A328951 Select[Range[3*10^6], DivisorSigma[0, #] + DivisorSigma[1, #] == 3# &] (* _Amiram Eldar_, Nov 10 2019 *) %o A328951 (Magma) [m: m in [1..10^7] | SumOfDivisors(m) - 2*m eq m - NumberOfDivisors(m)]; %o A328951 (PARI) isok(m) = my(f=factor(m)); sigma(f) + numdiv(m) == 3*m; \\ _Michel Marcus_, Nov 13 2019 %Y A328951 Cf. A000005, A000203, A033880, A049820, A056076. %Y A328951 Cf. A083874 (numbers m such that sigma(m) + tau(m) = 2m). %Y A328951 Cf. A011251 (numbers m such that sigma(m) + phi(m) = 3m). %Y A328951 Cf. A329104 (numbers m with abundance A(m) = tau(m)). %K A328951 nonn,more %O A328951 1,1 %A A328951 _Jaroslav Krizek_, Nov 10 2019 %E A328951 a(4) from _Martin Ehrenstein_, Jul 25 2023