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Search: id:A033550
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| 2, 2, 5, 15, 43, 118, 316, 836, 2199, 5769, 15117, 39592, 103670, 271430, 710633, 1860483, 4870831, 12752026, 33385264, 87403784, 228826107, 599074557, 1568397585, 4106118220, 10749957098, 28143753098, 73681302221, 192900153591
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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Also distinct compositions of the wheel graph W_n. - Ralf Stephan (ralf(AT)ark.in-berlin.de), Jan 02 2003
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LINKS
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A. Knopfmacher, M.E. Mays, Graph Compositions. I: Basic Enumeration, Integers 1(2001), #A04.
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FORMULA
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a(n)=3a(n-1)-a(n-2)+n-1. G.f.: (2-8x+11x^2-4x^3)/((1-3x+x^2)(1-x)^2).
a(n)=[3/2+(1/2)*sqrt(5)]^n-n+[3/2-(1/2)*sqrt(5)]^n, with n>=0 - Paolo P. Lava (ppl(AT)spl.at), Jun 12 2008
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PROGRAM
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(PARI) a(n)=fibonacci(2*n+1)+fibonacci(2*n-1)-n
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CROSSREFS
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Sequence in context: A112709 A098888 A089848 this_sequence A032130 A158059 A019099
Adjacent sequences: A033547 A033548 A033549 this_sequence A033551 A033552 A033553
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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