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

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A040148 Primes p such that x^4 = 20 has no solution mod p. 2
3, 7, 13, 17, 23, 37, 41, 43, 47, 53, 67, 73, 83, 89, 97, 101, 103, 107, 109, 113, 127, 137, 149, 157, 163, 167, 173, 181, 193, 197, 223, 227, 233, 241, 257, 263, 269, 277, 281, 283, 293, 307, 313, 317, 337, 347 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Complement of A040147 relative to A000040. - Vincenzo Librandi, Sep 18 2012

LINKS

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

MATHEMATICA

ok[p_]:= Reduce[Mod[x^4 - 20, p] == 0, x, Integers] == False; Select[Prime[Range[100]], ok] (* Vincenzo Librandi, Sep 18 2012  *)

PROG

(MAGMA) [p: p in PrimesUpTo(500) | not exists{x : x in ResidueClassRing(p) | x^4 eq 20} ]; // Vincenzo Librandi, Sep 18 2012

CROSSREFS

Sequence in context: A191028 A034914 A034913 * A097957 A071774 A019403

Adjacent sequences:  A040145 A040146 A040147 * A040149 A040150 A040151

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 18 02:33 EST 2021. Contains 340249 sequences. (Running on oeis4.)