%I #11 Jul 29 2017 04:19:04
%S 0,1,2,5,18,74,371,2178
%N Subset of A008989 containing one or more simple loops.
%C It appears (although it is not certain) that A268571(n) = A008989(n) - a(n).
%H Guy Valette, <a href="http://dx.doi.org/10.1007/s40598-016-0049-3">A Classification of Spherical Curves Based on Gauss Diagrams</a>, Arnold Math. J. (2016) 2:383-405, DOI 10.1007/s40598-016-0049-3.
%Y Cf. A008989, A268571.
%K nonn,more
%O 0,3
%A _N. J. A. Sloane_, Jul 17 2017