A307579 - OEIS

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, 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

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OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

EXAMPLE

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

MAPLE

filter:= proc(k) local F, i, s, t;

F:= ifactors(k)[2];

s:= `*`(k, seq(1-1/F[i, 1], i=1..nops(F)));

t:= `*`(seq((F[i, 1]-1)^F[i, 2], i=1..nops(F)));