A072392 Numbers n such that reverse(n) = phi(n) (mod n).

21, 27, 37, 63, 270, 291, 397, 1545, 1853, 2991, 6102, 15503, 27036, 48776, 198683, 200882, 274536, 1061361, 2348128, 2723436, 2746836, 3542805, 3564217, 3868867, 3962197, 4438616, 19844683, 46676013, 69460293, 198444683, 202195682, 297828396, 309520655

Offset

1,1

Links

Table of n, a(n) for n=1..33.

Example

reverse(48776) = 67784 = 19008 (mod 48776) and 19008 = phi(48776), so 48776 is a term of the sequence.

Mathematica

Select[Range[10^5], Mod[ FromDigits[Reverse[IntegerDigits[n]]], # ] == EulerPhi[ # ] &]
Select[Range[45*10^5], Mod[IntegerReverse[#], #]==EulerPhi[#]&] (* The program generates the first 26 terms of the sequence. *) (* Harvey P. Dale, Feb 05 2025 *)

Crossrefs

Cf. A000010, A103168.

Sequence in context: A206347 A362008 A247316 * A144415 A098898 A098768

Adjacent sequences: A072389 A072390 A072391 * A072393 A072394 A072395

Keyword

base,nonn

Author

Joseph L. Pe, Jul 21 2002

Extensions

More terms from Sean A. Irvine, Sep 28 2024

Status

approved