

A306224


a(n) is the smallest prime p such that n is not a square mod p.


1



3, 5, 5, 3, 11, 13, 3, 5, 7, 3, 7, 5, 3, 11, 7, 3, 5, 5, 3, 11, 13, 3, 5, 13, 3, 11, 5, 3, 7, 7, 3, 5, 5, 3, 19, 7, 3, 5, 7, 3, 13, 5, 3, 7, 11, 3, 5, 5, 3, 7, 7, 3, 5, 13, 3, 11, 5, 3, 11, 7, 3, 5, 5, 3, 7, 19, 3, 5, 11, 3, 7, 5, 3, 7, 11, 3, 5, 5, 3, 11, 7, 3, 5, 13, 3, 7, 5
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OFFSET

1,1


COMMENTS

a(n) is the smallest odd prime p such that Kronecker(n,p) = 1.
A companion sequence to A144294.
Conjecture: lim sup log(a(n))/log(n) = 0.


LINKS

Table of n, a(n) for n=1..87.


FORMULA

a(n) = 3 if and only if n == 1 (mod 3).
a(n) = 5 if and only if n == 2, 3, 8, 12 (mod 15).


PROG

(PARI) a(n) = forprime(p=3, , if(kronecker(n, p)<0, return(p)))


CROSSREFS

Cf. A144294.
See A306220 for another version.
Sequence in context: A328154 A249304 A333906 * A189202 A153098 A329509
Adjacent sequences: A306221 A306222 A306223 * A306225 A306226 A306227


KEYWORD

nonn


AUTHOR

Jianing Song, Jan 30 2019


STATUS

approved



