

A076262


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 three generators that require exactly k multiplications for their formation.


1




OFFSET

2,1


LINKS

Table of n, a(n) for n=2..11.


EXAMPLE

T(4,2)= 9 because each of aaaa,bbbb,cccc,abab,acac,baba,bcbc,caca,cbcb can be formed in just two multiplications: e.g. ab=a*b, abab=ab*ab.


CROSSREFS

Cf. A076261.
Sequence in context: A057405 A167354 A005066 * A167301 A177741 A182213
Adjacent sequences: A076259 A076260 A076261 * A076263 A076264 A076265


KEYWORD

more,nonn,tabl


AUTHOR

Colin Mallows, Oct 03 2002


STATUS

approved



