A211941 Number of distinct regular languages over binary alphabet, whose minimum regular expression has reverse Polish length n.

4, 2, 7, 13, 32, 90, 189, 580, 1347, 3978

Offset

1,1

Links

Table of n, a(n) for n=1..10.

Hermann Gruber, Jonathan Lee, and Jeffrey Shallit, Enumerating regular expressions and their languages, arXiv:1204.4982v1 [cs.FL], 2012.

Crossrefs

Sequence in context: A255140 A108167 A261690 * A050105 A367209 A348873

Adjacent sequences: A211938 A211939 A211940 * A211942 A211943 A211944

Keyword

nonn,hard

Author

Hermann Gruber, Apr 26 2012

Status

approved