

A076261


Triangle T(n,k) (n >= 2, 1 <= k <= n1) read by rows, where T(n,k) is the number of words of length n in the free group on two generators that require exactly k multiplications for their formation.


1



4, 0, 8, 0, 4, 12, 0, 0, 18, 14, 0, 0, 10, 44, 10, 0, 0, 0, 50, 74, 4
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OFFSET

2,1


LINKS

Table of n, a(n) for n=2..22.


EXAMPLE

T(4,2)=4 because we can generate each of aaaa,abab,baba,bbbb with just two multiplications: e.g. ab=a*b, abab=ab*ab.


CROSSREFS

Cf. A076262.
Sequence in context: A261278 A222609 A247848 * A070802 A114401 A304440
Adjacent sequences: A076258 A076259 A076260 * A076262 A076263 A076264


KEYWORD

more,nonn,tabl


AUTHOR

Colin Mallows, Oct 03 2002


STATUS

approved



