A076212 Numbers n such that n and Fibonacci(n) have the same number of prime factors.

1, 3, 5, 7, 9, 10, 11, 13, 14, 17, 22, 23, 26, 29, 34, 43, 47, 64, 83, 94, 121, 131, 137, 359, 431, 433, 449, 509, 569, 571

Offset

1,2

Comments

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.

Links

Table of n, a(n) for n=1..30.

Example

a(6)=9 because 9 and 9th Fibonacci number (i.e. 34) have the same number of prime factors i.e. 2

Maple

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, Feb 15 2006

Mathematica

Omega[n_] := Apply[Plus, Transpose[FactorInteger[n]][[2]]]; Flatten[Append[{1}, Select[Range[3, 150], Omega[ # ] == Omega[Fibonacci[ # ]] &]]]

Crossrefs

Sequence in context: A237287 A237046 A370421 * A085621 A324101 A364695

Adjacent sequences: A076209 A076210 A076211 * A076213 A076214 A076215

Keyword

more,nonn

Author

Joseph L. Pe, Nov 03 2002

Extensions

359 from Harvey P. Dale, May 01 2008

Edited by R. J. Mathar, Aug 11 2008

More terms from D. S. McNeil, Dec 23 2010

Status

approved