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 A014949 Numbers n such that n divides 8^n - 1. 15

%I

%S 1,7,49,343,889,2359,2401,6223,16513,16807,43561,112903,115591,117649,

%T 299593,304927,790321,794983,809137,823543,2033143,2097151,2134489,

%U 5532247,5564881,5663959,5764801,13549249,14232001,14338681,14680057,14941423,34591207,38048311,38725729

%N Numbers n such that n divides 8^n - 1.

%C For all k, 7^k is in the sequence. - _Benoit Cloitre_, Mar 05 2002

%C From _Alexander Adamchuk_, May 16 2010: (Start)

%C 7 divides a(n) for n>1.

%C Prime divisors of a (n) in the order of their first appearance are {7, 127, 337, 2287, 15241, 14407, 18199, 42463, ...}. (End)

%H M. F. Hasler, <a href="/A014949/b014949.txt">Table of n, a(n) for n = 1..64</a>

%o (PARI) is(n)=Mod(8,n)^n==1 \\ _Charles R Greathouse IV_, Nov 04 2016

%K nonn

%O 1,2