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Search: id:A076212
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| A076212 |
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Numbers n such that n and Fibonacci(n) have the same number of prime factors. |
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+0
1
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| 1, 3, 5, 7, 9, 10, 11, 13, 14, 17, 22, 23, 26, 29, 34, 43, 47, 64, 83, 94, 121, 131, 137, 359
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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More precisely, numbers n such that Omega(n) = Omega(Fibonacci(n)), where Omega(n) (A001222) denotes the number of prime factors of n, counting multiplicity.
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EXAMPLE
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a(6)=9 because 9 and 9th Fibonacci number (i.e. 34) have the same number of prime factors i.e. 2
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MAPLE
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with(numtheory): with(combinat): a:=proc(n) if bigomega(n)=bigomega(fibonacci(n)) then n else fi end: seq(a(n), n=1..150); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Feb 15 2006
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MATHEMATICA
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Omega[n_] := Apply[Plus, Transpose[FactorInteger[n]][[2]]]; Flatten[Append[{1}, Select[Range[3, 150], Omega[ # ] == Omega[Fibonacci[ # ]] &]]]
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KEYWORD
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more,nonn,new
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Nov 03 2002
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EXTENSIONS
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359 from Harvey P. Dale (hpd1(AT)nyu.edu), May 01 2008
Edited by R. J. Mathar, Aug 11 2008
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