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 A098215 #12 Jul 26 2015 01:35:57
%S A098215 136,261,295,493,1218,1576,15976,159976,715381,717181,746341,987109,
%T A098215 1585576,5989003,13390567,14400136,19326607,78753211,144144136,
%U A098215 145454536,158401576,275675661,713791681,737098261,1440000136,1441584136,1454414536,1455998536
%N A098215 Numbers n such that reverse(sigma(n)) = n - phi(n) = cototient(n).
%e A098215 n=5989003: sigma(n) = 5994000 and n - phi(n) = 4995
%t A098215 Do[ If[ FromDigits[ Reverse[ IntegerDigits[ DivisorSigma[1, n]]]] == n - EulerPhi[n], Print[n]], {n, 10^8}] (* _Robert G. Wilson v_, Oct 23 2004 *)
%Y A098215 Cf. A069225, A000203, A000010.
%K A098215 base,nonn
%O A098215 1,1
%A A098215 _Labos Elemer_, Oct 22 2004
%E A098215 More terms from _Robert G. Wilson v_, Oct 27 2004
%E A098215 a(19)-a(28) from _Donovan Johnson_, Jan 14 2011