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 A114930 #14 Aug 13 2019 07:22:42
%S A114930 6180,27630,2914830,4471740,27000630,637062480,27000000630,
%T A114930 679410757980,4412687534631,4421625783741
%N A114930 Numbers n such that phi(n)=2*reversal(n).
%C A114930 If m>1 and p=3*10^m+7 is prime then 90*p is in the sequence because phi(90*p)=phi(90)*phi(p)=24*(3*10^m+6)=2*(36*10^m+72) =2*reversal(27*10^m+63)=2*reversal(9*p)=2*reversal(90*p). Note that 30 divides all known terms of this sequence. Next term is greater than 11*10^7.
%C A114930 a(11) > 10^13. - _Giovanni Resta_, Aug 12 2019
%e A114930 637062480 is a term because phi(637062480) = 2*84260736 = 2*reversal(637062480).
%t A114930 Do[If[EulerPhi[n]==2*FromDigits[Reverse[IntegerDigits[n]]], Print[n]], {n, 110000000}]
%Y A114930 Cf. A000010, A004086, A069215, A114930, A136539, A114931, A136538.
%K A114930 nonn,base,more
%O A114930 1,1
%A A114930 _Farideh Firoozbakht_, Jan 29 2006
%E A114930 a(6)-a(8) from _Giovanni Resta_, Oct 28 2012
%E A114930 a(9)-a(10) from _Giovanni Resta_, Aug 12 2019