%I #18 Feb 22 2021 14:10:15
%S 6,4,26,62,244,920,3133,13529,48388,208634
%N Number of distinct regular languages over 4-ary alphabet, whose minimum regular expression has reverse Polish length n.
%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 Cf. A211946.
%K nonn,more
%O 1,1
%A _Hermann Gruber_, Apr 26 2012