The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A057490 Numbers k that divide 8^k + 7^k + 6^k + 5^k + 4^k + 3^k + 2^k. 1
1, 5, 7, 25, 35, 49, 125, 175, 245, 301, 343, 455, 625, 875, 1225, 1295, 1435, 1505, 1715, 1765, 2107, 2191, 2401, 3125, 4375, 6125, 7525, 8575, 10535, 11375, 12005, 12943, 14063, 14749, 15625, 16807, 21875, 22295, 30625, 35875, 37625, 42875, 52675, 60025, 64715, 70315, 73745, 78125, 80375, 84035, 90601, 93275 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Contains A003595. The first term not in A003595 is 301. Is 1 the only term not divisible by 5 or 7? - Robert Israel, Feb 22 2017
No term is divisible by 3. 5 and 7 are the only primes in this sequence. - Altug Alkan, Feb 23 2017
LINKS
MAPLE
select(t -> add(i &^ t, i=2..8) mod t = 0, [$1..10^6]); # Robert Israel, Feb 22 2017
MATHEMATICA
Select[ Range[ 10^5 ], Mod[ PowerMod[ 8, #, # ] + PowerMod[ 7, #, # ] + PowerMod[ 6, #, # ] + PowerMod[ 5, #, # ] + PowerMod[ 4, #, # ] + PowerMod[ 3, #, # ] + PowerMod[ 2, #, # ], # ] == 0 & ]
Select[Range[100000], Mod[Total[PowerMod[Range[2, 8], #, #]], #]==0&] (* Harvey P. Dale, Jul 28 2021 *)
CROSSREFS
Cf. A003595.
Sequence in context: A037374 A056717 A072370 * A057253 A003595 A018697
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Sep 22 2000
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 18 22:34 EDT 2024. Contains 373487 sequences. (Running on oeis4.)