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A094928 Let p = n-th prime == 1 mod 8 (A007519); a(n) = smallest prime q such that p is not a square mod q. 3
3, 3, 5, 3, 5, 3, 3, 5, 3, 7, 3, 3, 5, 5, 3, 3, 7, 5, 3, 5, 3, 3, 5, 3, 7, 3, 3, 5, 3, 7, 3, 3, 3, 3, 5, 3, 3, 11, 5, 3, 3, 11, 5, 3, 11, 3, 7, 3, 5, 7, 3, 3, 3, 3, 7, 3, 3, 7, 5, 3, 3, 5, 5, 11, 5, 3, 3, 5, 5, 3, 7, 5, 3, 5, 3, 7, 3, 7, 3, 5, 3, 3, 3, 5, 11, 5, 3, 5, 3, 3, 13, 5, 3, 3, 3, 3, 5, 5, 3, 5, 3, 7 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

M. Kneser, Quadratische Formen, Springer, 2002; see Hilfssatz 18.3.

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A094929(A269704(n)). - Robert Israel, May 06 2019

EXAMPLE

n=3, p = 73, a(3) = q = 5: Legendre(73,5) = -1.

MAPLE

f:= proc(p) local q;

     q:= 3:

     do

      if numtheory:-quadres(p, q) = -1 then return q fi;

      q:= nextprime(q);

     od;

end proc:

map(f, select(isprime, [seq(p, p=1..10000, 8)])); # Robert Israel, May 06 2019

MATHEMATICA

f[n_] := Prime[ Position[ JacobiSymbol[n, Select[Range[3, n - 1], PrimeQ[ # ] &]], -1][[1, 1]] + 1]; f /@ Select[ Prime[ Range[435]], Mod[ #, 8] == 1 &] (* Robert G. Wilson v, Jun 23 2004 *)

CROSSREFS

Cf. A007519, A002224, A144294, A269704.

Subsequence of A094929.

Sequence in context: A014780 A216199 A073081 * A178984 A065507 A182731

Adjacent sequences:  A094925 A094926 A094927 * A094929 A094930 A094931

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Jun 19 2004

EXTENSIONS

More terms from Robert G. Wilson v, Jun 23 2004

STATUS

approved

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Last modified May 24 06:53 EDT 2019. Contains 323529 sequences. (Running on oeis4.)