

A014946


Numbers n such that n divides 6^n1.


15



1, 5, 25, 125, 625, 1555, 3125, 7775, 15625, 38875, 78125, 194375, 390625, 483605, 971875, 1953125, 2418025, 4859375, 9673655, 9765625, 12090125, 24296875, 48368275, 48828125, 60450625, 120909025, 121484375, 150401155, 241841375
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OFFSET

1,2


COMMENTS

Includes all powers of 5. If a term such as 1555 = 5*311 occurs, so does any number of the form 5^a * 311^b for a>3.
Contribution from Alexander Adamchuk, May 16 2010: (Start)
All terms that are not the powers of 5 are divisible by 5 and 311.
Prime divisors of a(n) are {5, 311, 6221 , 15551, 155501, ...}. (End)


LINKS

Table of n, a(n) for n=1..29.


MATHEMATICA

Select[ Range[ 5*10^7], PowerMod[6, #, # ] == 1 & ]


PROG

(PARI) is(n)=Mod(6, n)^n==1 \\ Charles R Greathouse IV, Nov 04 2016


CROSSREFS

Sequence in context: A250357 A216125 A057831 * A188580 A132839 A206451
Adjacent sequences: A014943 A014944 A014945 * A014947 A014948 A014949


KEYWORD

nonn


AUTHOR

Olivier Gérard


EXTENSIONS

Better description from Benoit Cloitre, Mar 06 2002
Edited and extended by Robert G. Wilson v, Jun 18 2002
a(25)a(45) from Alexander Adamchuk, May 16 2010


STATUS

approved



