A029702 Q(sqrt(n)) has class number 2.

10, 15, 26, 30, 34, 35, 39, 42, 51, 55, 58, 65, 66, 70, 74, 78, 85, 87, 91, 95, 102, 105, 106, 110, 111, 114, 115, 119, 122, 123, 138, 143, 146, 154, 155, 159, 165, 174, 178, 182, 183, 185, 186, 187, 190, 194, 202, 203, 205, 215, 218, 221, 222, 230, 238, 246

Offset

1,1

Comments

Smallest term that is in A146209 but not this sequence is 79, since Q(sqrt(79)) has class number 3. - Alonso del Arte, Aug 25 2014

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Index entries for sequences related to quadratic fields

Mathematica

Select[Range[246], SquareFreeQ[#] && NumberFieldClassNumber@Sqrt[#] == 2 &] (* Arkadiusz Wesolowski, Oct 22 2012 *)

Prog

(PARI)
A007947(n)={my(p); p=factor(n)[, 1]; prod(i=1, length(p), p[i]); }
{ for (n=2, 10^3,
    if ( n!=A007947(n), next() );
    K = bnfinit(x^2 - n);
    if ( K.cyc == [2], print1( n, ", ") );
); }
/* Joerg Arndt, Oct 18 2012 */

Crossrefs

Cf. A003172, A029703-A029705, A218038-A218042.

Sequence in context: A231643 A276541 A146209 * A053330 A051990 A246447

Adjacent sequences: A029699 A029700 A029701 * A029703 A029704 A029705

Keyword

nonn

Author

Paolo Dominici (pl.dm(AT)libero.it)

Status

approved