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A029702 Q(sqrt(n)) has class number 2. 13
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 (list; graph; refs; listen; history; text; internal format)
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
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
Sequence in context: A231643 A276541 A146209 * A053330 A051990 A246447
KEYWORD
nonn
AUTHOR
Paolo Dominici (pl.dm(AT)libero.it)
STATUS
approved

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Last modified May 29 10:46 EDT 2024. Contains 372938 sequences. (Running on oeis4.)