A094619 Fundamental discriminants of real quadratic number fields with class number 2.

40, 60, 65, 85, 104, 105, 120, 136, 140, 156, 165, 168, 185, 204, 205, 220, 221, 232, 264, 265, 273, 280, 285, 296, 305, 312, 345, 348, 357, 364, 365, 377, 380, 385, 408, 424, 429, 440, 444, 456, 460, 465, 476, 481, 485, 488, 492, 493, 533, 545, 552, 561, 565

Offset

1,1

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 1000 terms from T. D. Noe)

Eric Weisstein's World of Mathematics, Class Number

Index entries for sequences related to quadratic fields

Mathematica

Select[Range[565], NumberFieldDiscriminant@Sqrt[#] == # && NumberFieldClassNumber@Sqrt[#] == 2 &] (* Arkadiusz Wesolowski, Oct 22 2012 *)

Prog

(PARI) is(n)=n>9 && isfundamental(n) && qfbclassno(n)==2 \\ Charles R Greathouse IV, Nov 05 2014
(Sage)
is_fund_and_qfbcn_1 = lambda n: is_fundamental_discriminant(n) and QuadraticField(n, 'a').class_number() == 2;
A094619 = lambda n: filter(is_fund_and_qfbcn_1, (1, 2, .., n));
A094619(600) # G. C. Greubel, Mar 01 2019

Crossrefs

Cf. A003656, A094612-A094614, A218156-A218160.

Sequence in context: A259061 A344408 A035120 * A052475 A182205 A195571

Adjacent sequences: A094616 A094617 A094618 * A094620 A094621 A094622

Keyword

nonn

Author

Eric W. Weisstein, May 14 2004

Status

approved