A046020 Discriminants of imaginary quadratic fields with class number 23 (negated).
647, 1039, 1103, 1279, 1447, 1471, 1811, 1979, 2411, 2671, 3491, 3539, 3847, 3923, 4211, 4783, 5387, 5507, 5531, 6563, 6659, 6703, 7043, 9587, 9931, 10867, 10883, 12203, 12739, 13099, 13187, 15307, 15451, 16267, 17203, 17851, 18379, 20323
Offset: 1
Links
- Giovanni Resta, Table of n, a(n) for n = 1..68 (full sequence, from Steven Arno et al.)
- Steven Arno, M. L. Robinson, Ferrell S. Wheeler, Imaginary quadratic fields with small odd class number, Acta Arith. 83 (1998) 295-330.
- Duncan A. Buell, Small class numbers and extreme values of L-functions of quadratic fields, Math. Comp., 31 (1977), 786-796.
- Keith Matthews, Tables of imaginary quadratic fields with small class numbers
- C. Wagner, Class Number 5, 6 and 7, Math. Comput. 65, 785-800, 1996.
- Eric Weisstein's World of Mathematics, Class Number.
- Index entries for sequences related to quadratic fields
Programs
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Mathematica
Reap[ Do[ If[ NumberFieldClassNumber[ Sqrt[-n] ] == 23, d = -NumberFieldDiscriminant[ Sqrt[-n] ]; Print[d]; Sow[d]], {n, 1, 21000}]][[2, 1]] // Union (* Jean-François Alcover, Oct 22 2012 *) -
PARI
select(n->qfbclassno(-n)==23, vector(22696, n, 4*n+3)) \\ Charles R Greathouse IV, Apr 25 2013
Extensions
68 discriminants in this sequence (proved).