%I A003649 M0054
%S A003649 1,1,1,1,1,2,1,1,1,2,1,1,1,1,1,2,1,2,1,1,2,2,1,1,2,1,2,1,1,1,2,1,2,1,2,
%T A003649 1,1,1,2,2,1,1,2,1,1,2,1,2,3,4,1,2,1,2,1,2,1,1,2,1,1,2,1,2,2,1,1,2,2,1,
%U A003649 2,2,1,2,2,2,1,1,4,1,1,1,1,2,1,1,3,2,4,2,1,1,2,2,1,1,2,1,1,2,1,1,4,1,2
%N A003649 Class number of real quadratic field Q(sqrt f), where f is the n-th square-free 
               number A005117(n).
%D A003649 D. A. Buell, Binary Quadratic Forms. Springer-Verlag, NY, 1989, pp. 224-241.
%D A003649 M. Pohst and H. Zassenhaus, Algorithmic Algebraic Number Theory, Cambridge 
               Univ. Press, 1989, p. 432.
%D A003649 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%H A003649 T. D. Noe, <a href="b003649.txt">Table of n, a(n) for n=2..6083</a> (for 
               squarefree numbers < 10000)
%H A003649 S. R. Finch, <a href="http://algo.inria.fr/bsolve/">Class number theory</
               a>
%H A003649 <a href="Sindx_Qua.html#quadfield">Index entries for sequences related 
               to quadratic fields</a>
%Y A003649 Sequence in context: A113120 A154843 A062557 this_sequence A003650 A059233 
               A143898
%Y A003649 Adjacent sequences: A003646 A003647 A003648 this_sequence A003650 A003651 
               A003652
%K A003649 nonn
%O A003649 2,6
%A A003649 N. J. A. Sloane (njas(AT)research.att.com) and Mira Bernstein