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A002146 Smallest prime == 7 (mod 8) where Q(sqrt(-p)) has class number 2n+1.
(Formerly M4377 N1841)
7
7, 23, 47, 71, 199, 167, 191, 239, 383, 311, 431, 647, 479, 983, 887, 719, 839, 1031, 1487, 1439, 1151, 1847, 1319, 3023, 1511, 1559, 2711, 4463, 2591, 2399, 3863, 2351, 3527, 3719 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
Conjecture: a(n) < A002148(n) for all n >= 1. - Jianing Song, Jul 20 2022
REFERENCES
D. A. Buell, Binary Quadratic Forms. Springer-Verlag, NY, 1989, pp. 224-241.
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
David Broadhurst and T. D. Noe, Table of n, a(n) for n = 0..28603
PROG
(PARI) a(n) = forprime(p=2, oo, if ((p % 8) == 7, if (qfbclassno(-p) == 2*n+1, return(p)))); \\ Michel Marcus, Jul 20 2022
CROSSREFS
Cf. A002147, A002148, A060651, A002143 (class numbers).
Sequence in context: A185007 A308732 A139035 * A336092 A184882 A073577
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified May 20 03:57 EDT 2024. Contains 372703 sequences. (Running on oeis4.)