%I A008988
%S A008988 1,1,2,6,21,97,579,3812
%N A008988 Number of immersions of oriented circle into unoriented sphere with n 
               double points.
%D A008988 V. I. Arnold, Topological Invariants of Plane Curves..., American Math. 
               Soc., 1994, p. 18.
%Y A008988 Sequence in context: A115089 A001928 A005638 this_sequence A061232 A020091 
               A008987
%Y A008988 Adjacent sequences: A008985 A008986 A008987 this_sequence A008989 A008990 
               A008991
%K A008988 nonn,nice
%O A008988 0,3
%A A008988 N. J. A. Sloane (njas(AT)research.att.com).
%E A008988 Two more terms from Guy H. Valette (guy.valette(AT)skynet.be), Feb 09 
               2004