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Search: id:A083859
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| 0, 1, 1, 4, 9, 41, 133, 673, 2737, 15130, 72181, 430739, 2320825, 14815529, 88005541, 596681296, 3843559137, 27515587661, 189933449365, 1428716457761, 10474213334761, 82448447397646, 637534807917701, 5233087759204967
(list; graph; listen)
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OFFSET
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0,4
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COMMENT
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if s(n) is a sequence of the form s(0) =0, s(1)=x,s(n)= s(n-1)+k(s(n-2) then s(k) = a(n)*x. For example if k= 7 and x= 5, s(7)= 0,5,5,40,75,355,880,3365 (3365= 673*5) [From Gary Detlefs (gdetlefs(AT)aol.com), Dec 04 2009]
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FORMULA
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a(n)=(((1+sqrt(4n+1))/2)^n-((1-sqrt(4n+1))/2)^n)/sqrt(4n+1)
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CROSSREFS
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Cf. A083860.
Sequence in context: A042887 A053908 A149165 this_sequence A070761 A149166 A149167
Adjacent sequences: A083856 A083857 A083858 this_sequence A083860 A083861 A083862
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KEYWORD
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easy,nonn,new
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), May 06 2003
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