A117296 Numbers n for which phi(n) is a palindrome.

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, 134, 138, 178, 184, 223, 230, 233, 263, 276, 283, 289, 293, 295, 301, 321, 381, 387, 411, 428, 441, 446, 466, 472, 508, 526, 535, 548, 566, 578, 586, 590

Offset: 1

Author

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

Keywords

• base
• nonn

Examples

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

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..2000

Crossrefs

Cf. A002113.

Programs

Mathematica

Select[Range[600],FromDigits[Reverse[IntegerDigits[EulerPhi[ # ]]]]==EulerPhi[ # ] &] (* Stefan Steinerberger, Apr 24 2006 *)
Select[Range[600],PalindromeQ[EulerPhi[#]]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 21 2020 *)

Extensions

Corrected and extended by Stefan Steinerberger, Apr 24 2006