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%I #15 Aug 12 2019 23:13:01
%S 1,3,15,129,270,833,5044,59815,9633693,26427528,4642779313,
%T 26594615202,62935243460,91770096041,1648209018135
%N Numbers n such that reverse(phi(n+1)) = phi(n).
%C a(12) > 25*10^9. - _Donovan Johnson_, Jun 09 2011
%C a(16) > 2*10^12. - _Giovanni Resta_, Aug 12 2019
%e n=59815: phi(n) = 40992, phi(n+1) = 29904 = rev(phi(n)).
%t Select[Range[60000], IntegerReverse[EulerPhi[# + 1]] == EulerPhi[#] &] (* _Giovanni Resta_, Aug 12 2019 *)
%o (PARI) isok(n) = eulerphi(n) == fromdigits(Vecrev(digits(eulerphi(n+1)))); \\ _Michel Marcus_, Aug 12 2019
%Y Cf. A004086, A069225, A074241, A074242.
%K nonn,base,more
%O 1,2
%A _Labos Elemer_, Sep 20 2002
%E a(9)-a(11) from _Donovan Johnson_, Jun 09 2011
%E a(12)-a(15) from _Giovanni Resta_, Aug 12 2019