%I #18 Mar 12 2014 17:16:00
%S 6,25,28,496,652,8128,10682,10828,33550336,44655764,8589869056,
%T 8623554304,137438691328
%N Numbers n such that sigma(n) - n = perfect number (A000396).
%C Also numbers n such that sum of the proper divisors of n (A001065) = perfect number (A000396).
%C Supersequence of perfect numbers (A000396).
%C a(14) > 10^12. - _Giovanni Resta_, Mar 01 2014
%C Up to a(13), note that the terms that are not perfect are deficient. - _Michel Marcus_, Mar 12 2014
%e Number 25 is a term because sigma(25) - 25 = 31 - 25 = 6 (perfect number).
%o (PARI) isok(n) = sigma(smn=sigma(n) - n) == 2*smn; \\ _Michel Marcus_, Mar 01 2014
%Y Cf. A000203 (sigma(n)).
%K nonn,more
%O 1,1
%A _Jaroslav Krizek_, Feb 28 2014
%E a(10) from _Michel Marcus_, Mar 01 2014
%E a(11)-a(13) from _Giovanni Resta_, Mar 01 2014