This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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 (list; graph; refs; listen; history; text; internal format)
 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 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: A282177 A184593 A249304 * A189202 A153098 A119280 Adjacent sequences:  A306221 A306222 A306223 * A306225 A306226 A306227 KEYWORD nonn AUTHOR Jianing Song, Jan 30 2019 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.

Last modified September 21 19:59 EDT 2019. Contains 327282 sequences. (Running on oeis4.)