A117296 - OEIS

%I #9 Apr 21 2020 12:04:06

%S 1,2,3,4,5,6,7,8,9,10,12,14,15,16,18,20,23,24,30,46,67,69,89,92,115,

%T 134,138,178,184,223,230,233,263,276,283,289,293,295,301,321,381,387,

%U 411,428,441,446,466,472,508,526,535,548,566,578,586,590

%N Numbers n for which phi(n) is a palindrome.

%H Harvey P. Dale, <a href="/A117296/b117296.txt">Table of n, a(n) for n = 1..2000</a>

%e 69 is in the sequence because phi(69)=44 which is a palindrome.

%t Select[Range[600],FromDigits[Reverse[IntegerDigits[EulerPhi[ # ]]]]==EulerPhi[ # ] &] (* _Stefan Steinerberger_, Apr 24 2006 *)

%t Select[Range[600],PalindromeQ[EulerPhi[#]]&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Apr 21 2020 *)

%Y Cf. A002113.

%K base,nonn

%O 1,2

%A Luc Stevens (lms022(AT)yahoo.com), Apr 23 2006

%E Corrected and extended by _Stefan Steinerberger_, Apr 24 2006