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Search: id:A115051
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| A115051 |
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Number of distinct prime factors of F(n + L(n)) where F(n) is the Fibonacci number and L(n) is the Lucas number, and n >= 2. |
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+0
2
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| 1, 1, 1, 3, 4, 5, 4, 4, 6, 15, 4, 9, 3
(list; graph; listen)
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OFFSET
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0,4
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COMMENT
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Added a(13)=9 from F(534) and a(14)=3 from F(857) using Kelly's factorizations. a(15)>=5 via F(1379) and a(16)=23 via F(2223). - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 23 2006
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LINKS
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B. Kelley, Factorizations
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EXAMPLE
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The first three terms are 1 since:
F(2 + L(2)) = 5 (a prime)
F(3 + L(3)) = 13 (a prime)
F(4 + L(4)) = 89 (a prime)
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MAPLE
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lucas := proc(n::integer) if n = 0 then RETURN(2) ; elif n = 1 then RETURN(1) ; else RETURN(combinat[fibonacci](n-1)+combinat[fibonacci](n+1)) ; fi ; end : for n from 2 to 100 do print(n+lucas(n), "...") ; tst := combinat[fibonacci](n+lucas(n)) ; an := nops(op(2, ifactors(tst))) ; print(an) ; od : - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 23 2006
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CROSSREFS
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Cf. A000045, A000032.
Sequence in context: A072006 A014238 A014250 this_sequence A094634 A114545 A085600
Adjacent sequences: A115048 A115049 A115050 this_sequence A115052 A115053 A115054
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KEYWORD
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nonn
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AUTHOR
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Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Feb 28 2006
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 23 2006
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