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 A001990 Let p be the n-th odd prime. a(n) is the least prime congruent to 5 modulo 8 such that Legendre(-a(n), q) = -Legendre(-2, q) for all odd primes q <= p. (Formerly M3953 N1632) 2
 5, 29, 29, 29, 29, 29, 29, 29, 23669, 23669, 23669, 23669, 23669, 23669, 1508789, 5025869, 9636461, 9636461, 9636461, 37989701, 37989701, 37989701, 37989701, 37989701, 240511301, 240511301 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Numbers so far are all 5 mod 24. - Ralf Stephan, Jul 07 2003 REFERENCES N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS D. H. Lehmer, E. Lehmer and D. Shanks, Integer sequences having prescribed quadratic character, Math. Comp., 24 (1970), 433-451. D. H. Lehmer, E. Lehmer and D. Shanks, Integer sequences having prescribed quadratic character, Math. Comp., 24 (1970), 433-451 [Annotated scanned copy] PROG (PARI) isok(p, oddpn) = {forprime(q=3, oddpn, if (kronecker(p, q) != -kronecker(-2, q), return (0)); ); return (1); } a(n) = {oddpn = prime(n+1); forprime(p=3, , if ((p%8) == 5, if (isok(p, oddpn), return (p)); ); ); } \\ Michel Marcus, Oct 18 2017 CROSSREFS Cf. A001988. Sequence in context: A057713 A124987 A002584 * A043062 A321701 A243012 Adjacent sequences:  A001987 A001988 A001989 * A001991 A001992 A001993 KEYWORD nonn AUTHOR EXTENSIONS Better name from Sean A. Irvine, Mar 06 2013 Name and offset corrected by Michel Marcus, Oct 18 2017 STATUS approved

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Last modified April 9 20:55 EDT 2020. Contains 333363 sequences. (Running on oeis4.)