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Search: id:A156664
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| 1, 2, 6, 16, 42, 108, 274, 688, 1714, 4244, 10458, 25672, 62826, 153372
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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A007318 * A052551, where A052551 = (1, 1, 3, 3, 7, 7, 15, 15,...).
G.f.: (x^2 - 2*x + 1)/(2*x^3 + 3*x^2 - 4*x + 1) [From Alexander R. Povolotsky (pevnev(AT)juno.com), Feb 15 2009]
a(n)=2*A000129(n+1)-2^n. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jun 15 2009]
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EXAMPLE
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a(3) = 16 = (1, 3, 3, 1) dot (1, 1, 3, 3) = (1 + 3 + 9 + 3).
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CROSSREFS
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A052551
Adjacent sequences: A156661 A156662 A156663 this_sequence A156665 A156666 A156667
Sequence in context: A143123 A152089 A102699 this_sequence A025169 A111282 A115730
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KEYWORD
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nonn
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AUTHOR
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Gary W. Adamson (qntmpkt(AT)yahoo.com), Feb 12 2009
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