A191089 Least prime p such that the first n primes are not squares mod p.

3, 5, 43, 43, 67, 67, 163, 163, 163, 163, 163, 163, 74093, 170957, 360293, 679733, 2004917, 2004917, 51599563, 51599563, 96295483, 96295483, 146161723, 1408126003, 1728061733, 1728061733, 1728061733, 1728061733, 1728061733, 1728061733

Offset

1,1

Comments

That is, the first n primes are quadratic non-residues mod p. A less restrictive form of A001992. Sequence A191088 is similar, but allows p to be composite. See A147972 for the square version.

Links

Table of n, a(n) for n=1..30.

Mathematica

Table[p = 2; While[Length[Select[Prime[Range[n]], JacobiSymbol[#, p] == -1 &]] < n, p = NextPrime[p]]; p, {n, 15}]

Prog

(PARI) q=2; forprime(k=3, 1e9, forprime(p=2, q, if(kronecker(p, k)>=0, next(2))); print1(k", "); q=nextprime(q+1); k--) \\ Charles R Greathouse IV, Oct 10 2011

Crossrefs

Cf. A001992, A147972, A191088.

Sequence in context: A216085 A219018 A191088 * A199345 A062633 A240559

Adjacent sequences: A191086 A191087 A191088 * A191090 A191091 A191092

Keyword

nonn

Author

T. D. Noe, May 25 2011

Extensions

a(16)-a(30) from Charles R Greathouse IV, Oct 10 2011

Status

approved