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 A049603 #18 Sep 06 2023 23:22:42
%S A049603 6,28,264,1104,3360,75840,6499584,151062912,2171581440,4686409728,
%T A049603 316023611904
%N A049603 (1+e)-sigma perfect numbers: (1+e) - sigma(x) = 2*x.
%C A049603 The function (1+e) - sigma(n) is defined in A051378. This sequence lists solutions to A051378(n) = 2*n.
%C A049603 a(12) > 10^12. - _Giovanni Resta_, Jun 12 2016
%e A049603 Factorizations: 2*3, 2^2*7, 2^3*3*11, 2^4*3*23, 2^5*3*5*7, 2^6*3*5*79, 2^8*3^2*7*13*31, 2^7*3^2*7*11*13*131, 2^10*3*5*7*19*1063.
%t A049603 (* Assuming all terms greater than 28 are multiple of 24 *) ok[n_] := 2*n == Times @@ (1 + Sum[First[#]^s, {s, Divisors[Last[#]]}] & ) /@ FactorInteger[n]; Reap[For[n = 2, n <= 2171581440, n = n + If[n < 48, 1, 24], If[ok[n], Print[n]; Sow[n]]]][[2, 1]] (* _Jean-François Alcover_, Jun 26 2012 *)
%Y A049603 Cf. A049599, A051378.
%K A049603 nonn,nice
%O A049603 1,1
%A A049603 _Yasutoshi Kohmoto_
%E A049603 151062912 inserted by _Jean-François Alcover_, Jun 26 2012
%E A049603 a(10)-a(11) from _Giovanni Resta_, Jun 12 2016