A307579 Numbers k such that A003958(k) does not divide phi(k).

9, 18, 25, 27, 45, 49, 50, 54, 63, 75, 81, 90, 98, 99, 100, 108, 117, 121, 125, 126, 135, 147, 150, 153, 156, 162, 169, 171, 175, 189, 196, 198, 207, 225, 234, 242, 243, 245, 250, 261, 270, 275, 279, 289, 294, 297, 300, 306, 315, 324, 325, 333, 338, 342, 343, 350, 351, 361, 363

Offset

1,1

Links

Table of n, a(n) for n=1..59.

Example

For n = 1 the a(1) = 9 because A003958(9) = 4 does not divide A000010(9) = 6.

Mathematica

Select[Range[2, 363], Mod[EulerPhi@ #, Times @@ Map[# /. {p_, e_} :> (p - 1)^e &, FactorInteger[#]]] != 0 &] (* Michael De Vlieger, Apr 21 2019 *)

Crossrefs

Contained in A013929.

Cf. A000010, A003557, A003958, A007947, A005117, A319927.

Sequence in context: A347247 A038837 A325359 * A319927 A034046 A069562

Adjacent sequences: A307576 A307577 A307578 * A307580 A307581 A307582

Keyword

nonn

Author

Juri-Stepan Gerasimov, Apr 15 2019

Status

approved