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A123223 Triangle read by rows: T(n,k) = number of trinary Lyndon words of length n with exactly k 1's +0
1
1, 2, 1, 1, 2, 0, 2, 4, 2, 0, 3, 8, 5, 2, 0, 6, 16, 16, 8, 2, 0, 9, 32, 38, 26, 9, 2, 0, 18, 64, 96, 80, 40, 12, 2, 0, 30, 128, 220, 224, 137, 56, 13, 2, 0, 56, 256, 512, 596, 448, 224, 74, 16, 2, 0, 99, 512, 1144, 1536, 1336, 806, 332, 96, 17, 2, 0, 186, 1024, 2560, 3840, 3840 (list; table; graph; listen)
OFFSET

0,2

COMMENT

Sum of rows equal to number of trinary Lyndon words A027376 first column (k=0) is equal to the number of binary Lyndon words A001037 third through sixth column (k=2,3,4,5) equal to A124720, A124721, A124722, A124723 T(n+1,n-1) entry equal to A042948

FORMULA

G.f. for columns (except for k=0) given by 1/k*sum_{d|k} mu(d) x^k/(1-2*x^d)^(k/d) T(0,0) = 1 and T(n,0) = 1/n*sum_{d|n} mu(d)*2^(n/d) T(n,n) = 0 if n>1, T(n,n-1) = 2

EXAMPLE

Triangle begins:

1,

2,1,

1,2,0,

2,4,2,0,

3,8,5,2,0,

6,16,16,8,2,0,

9,32,38,26,9,2,0,

18,64,96,80,40,12,2,0,

T(n,1) = 2^(n-1) because all words beginning with a 1 and consisting of the rest 2's or 3's are trinary Lyndon words with exactly one 1.

CROSSREFS

Cf. A027376, A001037, A124720, A124721, A124722, A124723, A051168, A042948.

Sequence in context: A039980 A055138 A155997 this_sequence A088226 A117586 A057594

Adjacent sequences: A123220 A123221 A123222 this_sequence A123224 A123225 A123226

KEYWORD

nonn,tabl

AUTHOR

Mike Zabrocki (zabrocki(AT)mathstat.yorku.ca), Nov 05 2006

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Last modified December 7 23:50 EST 2009. Contains 170430 sequences.


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