This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A029702 #22 Aug 25 2014 13:09:26
%S A029702 10,15,26,30,34,35,39,42,51,55,58,65,66,70,74,78,85,87,91,95,102,105,
%T A029702 106,110,111,114,115,119,122,123,138,143,146,154,155,159,165,174,178,
%U A029702 182,183,185,186,187,190,194,202,203,205,215,218,221,222,230,238,246
%N A029702 Q(sqrt(n)) has class number 2.
%C A029702 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
%H A029702 Charles R Greathouse IV, <a href="/A029702/b029702.txt">Table of n, a(n) for n = 1..10000</a>
%H A029702 <a href="/index/Qua#quadfield">Index entries for sequences related to quadratic fields</a>
%t A029702 Select[Range[246], SquareFreeQ[#] && NumberFieldClassNumber@Sqrt[#] == 2 &] (* _Arkadiusz Wesolowski_, Oct 22 2012 *)
%o A029702 (PARI)
%o A029702 A007947(n)={my(p); p=factor(n)[, 1]; prod(i=1, length(p), p[i]); }
%o A029702 { for (n=2, 10^3,
%o A029702 if ( n!=A007947(n), next() );
%o A029702 K = bnfinit(x^2 - n);
%o A029702 if ( K.cyc == [2], print1( n, ", ") );
%o A029702 ); }
%o A029702 /* _Joerg Arndt_, Oct 18 2012 */
%Y A029702 Cf. A003172, A029703-A029705, A218038-A218042.
%K A029702 nonn
%O A029702 1,1
%A A029702 Paolo Dominici (pl.dm(AT)libero.it)