%I #13 Feb 11 2014 19:09:01

%S 91,874,3411,9093,40112,44252,54081,67284,80224,90933,91503,4961782,

%T 5400081,5726691,8750834,9076921,9155055,54000081,62023914,90766921,

%U 93079231,430770922,540000081,636355044,808618664,907666921,928709013,4050394312,4262971312

%N Numbers n such that n - reverse(n) = phi(n).

%C If m>1 and p=2*10^m+3 is prime then n=27*p is in the sequence because n-reversal(n)=27*(2*10^m+3)-reversal(27*(2*10^m+3))= (54*10^m+81)-(18*10^m+45)=36*10^m+36=18*(2*10^m+2)=phi(27)* phi(2*10^m+3)=phi(27*(2*10^m+3))=phi(n). Also if m>2 and p=(389*10^m+109)/3 is prime then 7*p is in the sequence (the proof is easy). Next term is greater than 2*10^8. - _Farideh Firoozbakht_, Jan 27 2006

%C a(51) > 10^12. - _Giovanni Resta_, Oct 28 2012

%H Giovanni Resta, <a href="/A072393/b072393.txt">Table of n, a(n) for n = 1..50</a>

%e 91 - 19 = 72 = phi(91), so 91 is a term of the sequence.

%t Select[Range[10^5], # - FromDigits[Reverse[IntegerDigits[n]]] == EulerPhi[ # ] &]

%Y Cf. A114926, A114927.

%K base,nonn

%O 1,1

%A _Joseph L. Pe_, Jul 21 2002

%E More terms from _Farideh Firoozbakht_, Jan 27 2006

%E a(22)-a(29) from _Donovan Johnson_, Dec 04 2011