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Search: id:A075100
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| A075100 |
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Number of terms of length < n that are needed on the way to computing all words of length n in the free monoid with two generators. |
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+0
3
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OFFSET
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1,3
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COMMENT
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I believe a(2n) = a(n)+ 2^n. I think a(7) = 28.
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EXAMPLE
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a(3) = 3 because we need only xx, xy, yy to generate each of xxx, xxy, xyx, yxx, xyy, yxy, yyx, yyy.
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CROSSREFS
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Cf. A075099, A003313, A124677.
Sequence in context: A023896 A128488 A117781 this_sequence A066861 A139063 A047341
Adjacent sequences: A075097 A075098 A075099 this_sequence A075101 A075102 A075103
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KEYWORD
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hard,more,nonn,obsc
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AUTHOR
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Colin Mallows (colinm(AT)research.avayalabs.com), Aug 31 2002
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EXTENSIONS
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Shouldn't a(2) = 2 ? Shouldn't a(3) = 5, because we need x, y, xx, xy, yy ? I'm confused! - njas, Dec 25 2006
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