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Search: id:A123915
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| A123915 |
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Number of binary words whose (unique) decreasing Lyndon decomposition is into Lyndon words each with an even number of 1's; EULER transform of A051841. |
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+0
1
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| 1, 1, 2, 3, 6, 11, 21, 39, 75, 143, 275, 528, 1020, 1971, 3821, 7414, 14419, 28072, 54739, 106847, 208815, 408470, 799806, 1567333, 3073916, 6032971, 11848693, 23285202, 45787650, 90085410, 177331748, 349243800
(list; graph; listen)
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OFFSET
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1,3
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FORMULA
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Prod_{n>=1} 1/(1-q^n)^A051841(n) = 1+sum_{n>=1} a(n) q^n
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EXAMPLE
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The binary words 00000, 01100, 00110, 01111, 00011, 00101 of length 5 decompose as 0*0*0*0*0, 011*0*0, 0011*0, 01111, 00011, 00101 and each subword has an even number of 1's, therefore a(5)=6
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CROSSREFS
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Cf. A051841.
Sequence in context: A049856 A113409 A092684 this_sequence A132832 A079116 A109222
Adjacent sequences: A123912 A123913 A123914 this_sequence A123916 A123917 A123918
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KEYWORD
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nonn
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AUTHOR
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Mike Zabrocki (zabrocki(AT)mathstat.yorku.ca), Oct 28 2006
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