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Number of distinct regular languages over 4-ary alphabet, whose minimum regular expression has reverse Polish length n.
1

%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