login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A124246 Numbers n such that n divides 5^n - 2. 11
1, 3, 123, 202884639, 242405133, 92273577267, 2670733723929, 81035221987959 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

No other terms below 10^15. Some larger terms: 60092749466423900486673922957841, 401021769827858799355246286337987697472836927856337282726789534497163. - Max Alekseyev, Oct 15 2016

LINKS

Table of n, a(n) for n=1..8.

MATHEMATICA

Do[If[Mod[(PowerMod[5, n, n]-2), n]==0, Print[n]], {n, 1000000000}]

PROG

(PARI) is(n)=Mod(5, n)^n==2 \\ Charles R Greathouse IV, Nov 04 2016

CROSSREFS

Solutions to 5^n == k (mod n): A067946 (k=1), A015951 (k=-1), this sequence (k=2), A123062 (k=-2), A123061 (k=3), A123052 (k=-3), A125949 (k=4), A123047 (k=-4), A123091 (k=5), A015891 (k=-5), A277350 (k=6), A277348 (k=-6).

Sequence in context: A078258 A258658 A222186 * A219010 A037118 A085531

Adjacent sequences:  A124243 A124244 A124245 * A124247 A124248 A124249

KEYWORD

nonn

AUTHOR

Farideh Firoozbakht, Nov 19 2006

EXTENSIONS

a(6)-a(8) from Max Alekseyev, Jul 28 2009, Jun 02 2010, Oct 15 2016

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 15 02:31 EDT 2020. Contains 335762 sequences. (Running on oeis4.)