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 A099650 #11 Oct 15 2013 22:32:35
%S A099650 456,828,7584,33462,1596048,1964544,19800384,26211264,31451136,
%T A099650 106805184,156868224,316113024,502349274,503291904,1557940992,
%U A099650 8024671392,8052965376,11697091872,22149447168,87877745664,443520605184,626058783744
%N A099650 Solutions to x+phi(x) = sigma(x)/2.
%C A099650 If 5*2^n-1 is prime then m=3*2^(n+1)*(5*2^n-1) is in the sequence because m+phi(m)=2^(n+1)*3*(5*2^n-1)+2^(n+1)*(5*2^n-2)=2^(n+1) *(20*2^n-5)=2^(n+1)*5*(2^(n+2)-1)=1/2*4*(2^(n+2)-1)*(5*2^n)= 1/2*sigma(3)*sigma(2^(n+1))*sigma(5*2^n-1)=1/2*sigma(3*2^(n+1) *(5*2^n-1))=1/2*sigma(m). So 3*2^(A001770+1)*(5*2^A001770-1) is a subsequence of this sequence. A110084 is this subsequence. Next term is greater than 10^8. - _Farideh Firoozbakht_, Aug 04 2005
%C A099650 a(23) > 10^12. - _Donovan Johnson_, Feb 29 2012
%e A099650 n=456: phi(456) = 144, sigma(456) = 1200.
%t A099650 Do[If[DivisorSigma[1, m] == 2m + 2 EulerPhi[m], Print[m]], {m, 100000000}] (Firoozbakht)
%Y A099650 Cf. A000010, A000203, A001770, A110084.
%K A099650 nonn
%O A099650 1,1
%A A099650 _Labos Elemer_, Nov 05 2004
%E A099650 Two more terms from _Farideh Firoozbakht_, Aug 04 2005
%E A099650 a(10)-a(22) from _Donovan Johnson_, Feb 29 2012