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A046013 Discriminants of imaginary quadratic fields with class number 16 (negated). 2
399, 407, 471, 559, 584, 644, 663, 740, 799, 884, 895, 903, 943, 1015, 1016, 1023, 1028, 1047, 1139, 1140, 1159, 1220, 1379, 1412, 1416, 1508, 1560, 1595, 1608, 1624, 1636, 1640, 1716, 1860, 1876, 1924, 1983, 2004, 2019, 2040, 2056, 2072 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

322 discriminants in this sequence (almost certainly but not proved).

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..322

Steven Arno, M. L. Robinson and Ferrel S. Wheeler, Imaginary quadratic fields with small odd class number, Acta Arithm. 83.4 (1998), 295-330

Duncan A. Buell, Small class numbers and extreme values of L-functions of quadratic fields, Math. Comp., 31 (1977), 786-796.

C. Wagner, Class Number 5, 6 and 7, Math. Comput. 65, 785-800, 1996.

Victor Y. Wang, On Hilbert 2-class fields and 2-towers of imaginary quadratic number fields, arXiv preprint arXiv:1508.06552, 2015

Eric Weisstein's World of Mathematics, Class Number.

Index entries for sequences related to quadratic fields

MATHEMATICA

Reap[ For[n = 1, n < 3000, n++, s = Sqrt[-n]; If[ NumberFieldClassNumber[s] == 16, d = -NumberFieldDiscriminant[s]; Print[d]; Sow[d]]]][[2, 1]] // Union (* Jean-Fran├žois Alcover, Oct 05 2012 *)

PROG

(PARI) ok(n)={isfundamental(-n) && qfbclassno(-n) == 16} \\ Andrew Howroyd, Jul 24 2018

CROSSREFS

Cf. A006203, A013658, A014602, A014603, A046002-A046020.

Sequence in context: A261768 A274446 A253598 * A176911 A202158 A126231

Adjacent sequences:  A046010 A046011 A046012 * A046014 A046015 A046016

KEYWORD

nonn,fini

AUTHOR

Eric W. Weisstein

STATUS

approved

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Last modified November 11 16:07 EST 2019. Contains 329019 sequences. (Running on oeis4.)