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Search: id:A165192
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| A165192 |
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a(0)=1 a(1)=2 a(3)=3, a(n) = a(n-1)-a(n-3). |
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+0
1
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| 1, 2, 3, 2, 0, -3, -5, -5, -2, 3, 8, 10, 7, -1, -11, -18, -17, -6, 12, 29, 35, 23, -6, -41, -64, -58, -17, 47, 105, 122, 75
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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a(n)=(-1)^n*A104771(n). G.f.: (1+x+x^2)/(1-x+x^3).
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EXAMPLE
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a(3)=2 because 2=3-1 where the 1,3 on the right of the equals sign are the first and third terms of the series.
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PROGRAM
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(Python) series = [1, 2, 3] for i in range(2, 30): .series.append((series[i] - series[i-1])+(series[i-1]-series[i-2])) print series
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CROSSREFS
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Cf. A104771
Sequence in context: A021435 A007325 A056619 this_sequence A104771 A056888 A111182
Adjacent sequences: A165189 A165190 A165191 this_sequence A165193 A165194 A165195
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KEYWORD
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easy,sign
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AUTHOR
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Ben Thurston (benpaulthurston(AT)gmail.com), Sep 06 2009
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EXTENSIONS
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Offset corrected and recurrence simplified by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 08 2009
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