%I #14 Feb 22 2021 13:21:53
%S 6,26,202,1917,20251,231152,2780936
%N Number of distinct finite languages over 4-ary alphabet, whose minimum regular expression has reverse Polish length 2n-1.
%H Hermann Gruber, Jonathan Lee, and Jeffrey Shallit, <a href="http://arxiv.org/abs/1204.4982">Enumerating regular expressions and their languages</a>, arXiv:1204.4982v1 [cs.FL], 2012.
%Y Bisection of A211945.
%K nonn,hard,more
%O 1,1
%A _Hermann Gruber_, Apr 26 2012