|
|
A003625
|
|
Primes congruent to {3, 5, 6} mod 7.
(Formerly M2487)
|
|
9
|
|
|
3, 5, 13, 17, 19, 31, 41, 47, 59, 61, 73, 83, 89, 97, 101, 103, 131, 139, 157, 167, 173, 181, 199, 223, 227, 229, 241, 251, 257, 269, 271, 283, 293, 307, 311, 313, 349, 353, 367, 383, 397, 409, 419, 433, 439, 461, 467, 479, 503, 509, 521, 523, 563, 577, 587, 593
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Inert rational primes in Q(sqrt(-7)).
For terms >= 13, sequence consists of primes p such that Sum_{k=0..p} binomial(2*k,k)^3) == 8 (mod p). - Benoit Cloitre, Aug 10 2003
Primes which cannot be written in the form a^2 + 7*b^2, where a >= 0, b >= 0. - V. Raman, Sep 08 2012
Conjecture: Also such primes p where the polynomial x^2 + x + 2 is irreducible over GF(p). - Federico Provvedi, Jul 21 2018
Primes that have -7 as a quadratic nonresidue, or equivalently, primes that are quadratic nonresidues modulo 7. - Jianing Song, Jul 21 2018
|
|
REFERENCES
|
H. Hasse, Number Theory, Springer-Verlag, NY, 1980, p. 498.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
|
|
LINKS
|
|
|
MATHEMATICA
|
Select[Prime[Range[800]], MemberQ[{3, 5, 6}, Mod[#, 7]]&] (* Vincenzo Librandi, Aug 04 2012 *)
|
|
PROG
|
(Magma) [p: p in PrimesUpTo(1000) | p mod 7 in [3, 5, 6]]; // Vincenzo Librandi, Aug 04 2012
(PARI) {a(n) = local( cnt, m ); if( n<1, return( 0 )); while( cnt < n, if( isprime( m++) && kronecker( -7, m )==-1, cnt++ )); m} /* Michael Somos, Aug 14 2012 */
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|