A218041 Numbers n such that Q(sqrt(n)) has class number 9.

1129, 1654, 3137, 3719, 4409, 4534, 5521, 5623, 5878, 6809, 7573, 7873, 9998, 10273, 10721, 10814, 11027, 11641, 12323, 12409, 12657, 13069, 13691, 14159, 15374, 15629, 16321, 16382, 17273, 17989, 18633, 19441, 21023, 21781, 22497, 22502, 23003, 23806

Offset: 1

Author

Arkadiusz Wesolowski, Oct 19 2012

Keywords

• nonn

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
• Eric Weisstein's World of Mathematics, Class Number

Crossrefs

Cf. A003172, A029702-A029705, A218038-A218040, A218042.

Programs

Mathematica

Select[Range[23806], SquareFreeQ[#] && NumberFieldClassNumber@Sqrt[#] == 9 &]

PARI

is(n)=issquarefree(n) && qfbclassno(if(n%4>1,4,1)*n)==9 \\ Charles R Greathouse IV, Jan 19 2017