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A076261 Triangle T(n,k) (n >= 2, 1 <= k <= n-1) 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

%I

%S 4,0,8,0,4,12,0,0,18,14,0,0,10,44,10,0,0,0,50,74,4

%N Triangle T(n,k) (n >= 2, 1 <= k <= n-1) 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.

%e 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.

%Y Cf. A076262.

%K more,nonn,tabl

%O 2,1

%A _Colin Mallows_, Oct 03 2002

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Last modified January 19 22:12 EST 2022. Contains 350466 sequences. (Running on oeis4.)