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 A039788 #14 Jun 10 2025 08:46:30
%S A039788 9,16,35,45,150,154,234,264
%N A039788 Numbers k such that phi(k) is equal to the product of (the sum of prime factors and the sum of exponents) of k.
%C A039788 Next term if it exists is greater than 10^7. - C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 29 2004
%C A039788 a(9) > 10^10, if it exists. - _Amiram Eldar_, Jun 10 2025
%e A039788 45 is a term since phi(45) = 24, 45 = 3^2*5^1, (3+5)*(2+1) = 24.
%t A039788 q[n_] := Module[{f = FactorInteger[n], p, e}, p = f[[;;, 1]]; e = f[[;;, 2]]; Times @@ ((p-1) * p^(e-1)) == Total[p] * Total[e]]; Select[Range[2, 300], q] (* _Amiram Eldar_, Jun 10 2025 *)
%o A039788 (PARI) for(n=1,10000000,f=factor(n);l=#f[,1];if(eulerphi(n)==sum(i=1,l,f[i,1])*sum(i=1,l,f[i,2]),print1(n,","))) (Ronaldo)
%o A039788 (PARI) isok(k) = if(k == 1, 0, my(f = factor(k)); eulerphi(f) == vecsum(f[,1]) * vecsum(f[,2])); \\ _Amiram Eldar_, Jun 10 2025
%Y A039788 Cf. A000010, A039697, A039774, A039789.
%K A039788 nonn,more
%O A039788 1,1
%A A039788 _Olivier Gérard_