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A000229
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a(n) is the least number such that the n-th prime is the least quadratic nonresidue for a(n) (a(n) is always a prime).
(Formerly M2684 N1074)
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7
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3, 7, 23, 71, 311, 479, 1559, 5711, 10559, 18191, 31391, 422231, 701399, 366791, 3818929, 9257329, 22000801, 36415991, 48473881, 175244281, 120293879, 427733329, 131486759
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OFFSET
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1,1
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COMMENTS
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For n>1, a(n) = prime(k), where k is the smallest number such that A053760(k) = prime(n).
One could make a case for setting a(1)=2, but a(1)=3 seems more in keeping with the spirit of the sequence.
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REFERENCES
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H. J. Godwin, On the least quadratic non-residue, Proc. Camb. Phil. Soc., 61 (1965), 671-672.
Hans Sali\'e, \"Uber die kleinste Primzahl, die eine gegebene Primzahl als kleinsten positiven quadratischen Nichtrest hat, Math. Nachr. 29 1965 113-114.
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).
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LINKS
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N. J. A. Sloane, Table of n, a(n) for n = 1..38 (from the web page of Tomas Oliveira e Silva)
Tomas Oliveira e Silva, Least primitive root of prime numbers
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EXAMPLE
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a(2)=7 because the second prime is 3 and 3 is the least quadratic nonresidue for 7, 14, 17, 31, 34, ... and 7 is the least of these.
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CROSSREFS
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Cf. A025021, A053760. For records see A133435.
Differs from A002223, A045535 at 12th term.
Sequence in context: A066768 A225914 A062241 * A133435 A079061 A191638
Adjacent sequences: A000226 A000227 A000228 * A000230 A000231 A000232
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KEYWORD
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nonn,nice
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AUTHOR
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N. J. A. Sloane.
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EXTENSIONS
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Definition corrected by Melvin J. Knight (MELVIN.KNIGHT(AT)ITT.COM), Dec 08 2006
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STATUS
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approved
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