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%I #12 Feb 08 2014 15:59:56
%S 2475247,26522529
%N Numbers n such that reversal(n) = sigma(n)+2n.
%C If p(m) = (1/101)*(25*10^(4m-1)-53) is prime then p(m) is a term of the sequence. a(1) = p(1) and p(2669) is the second term of this form, which is a 10675-digit prime. This implies a(3) exists and a(3) <= 10^10675. a(3) is greater than 10^9.
%C a(3) > 10^13. - _Giovanni Resta_, Feb 08 2014
%t Do[If[FromDigits[Reverse[IntegerDigits[n]]]==DivisorSigma[1,n]+2n,Print[n]],{n,27000000}]
%Y Cf. A000010, A000203, A004086.
%K nonn,base,bref,more
%O 1,1
%A _Farideh Firoozbakht_, Nov 15 2013