%I A001989 M3756 N1535
%S A001989 1,1,5,7,7,7,9,53,73,83,83,83,157,157,185,185,185,1927,2295,2273,5313,
               5313,
%T A001989 7173,9529,18545,18545,18545,18545,22635,22635,66011,121725,344909,344909
%N A001989 Class numbers of quadratic fields.
%D A001989 D. H. Lehmer, E. Lehmer and D. Shanks, Integer sequences having prescribed 
               quadratic character, Math. Comp., 24 (1970), 433-451.
%D A001989 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A001989 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%Y A001989 Sequence in context: A093723 A065773 A114916 this_sequence A086056 A154475 
               A137755
%Y A001989 Adjacent sequences: A001986 A001987 A001988 this_sequence A001990 A001991 
               A001992
%K A001989 nonn
%O A001989 3,3
%A A001989 N. J. A. Sloane (njas(AT)research.att.com).