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A211942 Number of distinct finite languages over binary alphabet, whose minimum regular expression has reverse Polish length 2n-1. 0
4, 7, 25, 109, 514, 2641, 14354, 81325, 475936, 2854145 (list; graph; refs; listen; history; text; internal format)
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: A276288 A219700 A151348 * A110413 A075686 A077441

Adjacent sequences:  A211939 A211940 A211941 * A211943 A211944 A211945

KEYWORD

nonn,hard

AUTHOR

Hermann Gruber, Apr 26 2012

STATUS

approved

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Last modified December 3 21:17 EST 2021. Contains 349468 sequences. (Running on oeis4.)