%I #11 Apr 05 2018 22:42:31
%S 1,3,6,20,57,240,954,4566,22641,121823,683307,4004055
%N Number of genus 0 unsensed hypermaps with n darts.
%H Timothy R. Walsh, <a href="http://www.info2.uqam.ca/~walsh_t/papers/GENERATING NONISOMORPHIC.pdf">Space-efficient generation of nonisomorphic maps and hypermaps</a>
%H T. R. Walsh, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL18/Walsh/walsh3.html">Space-Efficient Generation of Nonisomorphic Maps and Hypermaps</a>, J. Int. Seq. 18 (2015) # 15.4.3
%Y Cf. A090371, A118094, A214819, A214820, A057005; A214821-A214823, A215017, A215018.
%K nonn,more
%O 1,2
%A _N. J. A. Sloane_, Aug 01 2012