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A075099
Minimal total number of multiplications needed to generate all words of length n in the free monoid on two generators.
2
0, 4, 11, 20, 42, 75
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OFFSET
1,2
COMMENTS
Benoit Jubin
(Jan 24 2009) suggests replacing "monoid" in the definition by "semigroup".
I believe a(2n) = a(n) + 2^(2n). I guess a(7) = 156.
LINKS
Table of n, a(n) for n=1..6.
EXAMPLE
a(3)=11 because each of xxx,xxy,xyx,xyy,yxx,yxy,yyx,yyy can be obtained in one step from xx,xy,yy and it takes three multiplications to produce xx, xy, yy.
CROSSREFS
Cf.
A075100
,
A124677
(another version).
Sequence in context:
A008174
A363604
A008262
*
A240784
A345434
A297961
Adjacent sequences:
A075096
A075097
A075098
*
A075100
A075101
A075102
KEYWORD
hard
,
more
,
nonn
AUTHOR
Colin Mallows
, Aug 31 2002
STATUS
approved
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Last modified April 25 08:27 EDT 2024. Contains 371964 sequences. (Running on oeis4.)