login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A040987 Primes p such that x^5 = 21 has no solution mod p. 2
31, 41, 71, 101, 131, 151, 181, 191, 211, 241, 251, 271, 281, 311, 331, 401, 431, 491, 521, 541, 571, 701, 751, 761, 811, 821, 881, 911, 941, 971, 991, 1021, 1031, 1051, 1061, 1091, 1151, 1181, 1201, 1291, 1301, 1321, 1361, 1381, 1471 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Complement of A040986 relative to A000040. - Vincenzo Librandi, Sep 19 2012

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

ok[p_] := Reduce[Mod[x^5 - 21, p] == 0, x, Integers] == False; Select[Prime[Range[300]], ok] (* Vincenzo Librandi, Sep 19 2012  *)

PROG

(MAGMA) [p: p in PrimesUpTo(1500) | not exists{x: x in ResidueClassRing(p) | x^5 eq 21}]; // Vincenzo Librandi, Sep 19 2012

CROSSREFS

Sequence in context: A202286 A141180 A176371 * A040180 A158754 A140458

Adjacent sequences:  A040984 A040985 A040986 * A040988 A040989 A040990

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified December 10 23:07 EST 2016. Contains 279021 sequences.