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A072556 Numbers n such that n and the n-th Fibonacci number have the same number of distinct prime factors. 0
1, 3, 4, 5, 7, 10, 11, 12, 13, 14, 17, 22, 23, 26, 29, 34, 43, 47, 83, 94, 131, 137, 359, 431, 433, 449, 509, 569, 571 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..29.

EXAMPLE

a(7)=10 because 10 and 10th Fibonacci number(i.e. 55) have the same number of prime factors i.e. 2. - Shyam Sunder Gupta, Feb 05 2006

MAPLE

with(combinat): with(numtheory): a:=proc(n) if nops(factorset(fibonacci(n)))=nops(factorset(n)) then n else fi end: seq(a(n), n=1..150); # Emeric Deutsch, Apr 02 2006

MATHEMATICA

Insert[Select[Range[1, 50], Length[FactorInteger[ # ]] ==Length[FactorInteger[Fibonacci[ # ]]] &], 2, 2] (* Stefan Steinerberger, Mar 20 2006 *)

CROSSREFS

Cf. A001221, A022307.

Sequence in context: A101760 A165713 A105148 * A047365 A048342 A159560

Adjacent sequences:  A072553 A072554 A072555 * A072557 A072558 A072559

KEYWORD

more,nonn

AUTHOR

Benoit Cloitre, Aug 06 2002

EXTENSIONS

More terms from Sascha Kurz, Jan 25 2003

Edited by R. J. Mathar, Aug 11 2008

STATUS

approved

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Last modified June 24 02:56 EDT 2021. Contains 345415 sequences. (Running on oeis4.)