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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 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

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