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Search: id:A132125
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| A132125 |
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Number of distinct Fibonacci divisors of the factorial of n. |
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+0
1
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| 1, 2, 3, 4, 5, 6, 7, 7, 7, 7, 8, 8, 9, 9, 9, 9, 10, 10, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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a(n)=A005086(A000142(n)).
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EXAMPLE
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a(8)=7 because 8!=40320=2^7*3^2*5*7 has the seven divisors 1, 2, 3, 5, 8, 21
and 144 which are also Fibonacci numbers.
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MAPLE
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A005086 := proc(n) local a, i, f; a := 0 ; for i from 2 do f := combinat[fibonacci](i) ; if f > n then RETURN(a) ; fi ; if n mod f = 0 then a := a+1 ; fi ; od: end: A000142 := proc(n) n! ; end: A := proc(n) A005086(A000142(n)) ; end: seq(A(n), n=1..80);
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CROSSREFS
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Cf. A005086, A000142, A000045.
Sequence in context: A141258 A117656 A101918 this_sequence A102672 A114955 A060207
Adjacent sequences: A132122 A132123 A132124 this_sequence A132126 A132127 A132128
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KEYWORD
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nonn
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AUTHOR
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R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 31 2007
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