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A114812 Indices of Fibonacci numbers with 3 prime factors when counted with multiplicity. 1
6, 15, 16, 21, 25, 33, 35, 37, 38, 39, 46, 49, 51, 58, 62, 65, 67, 82, 86, 103, 106, 119, 122, 139, 142, 145, 158, 166, 179, 181, 226, 233, 235, 241, 257, 263, 274, 281, 299, 301, 317, 337, 383, 389, 419, 457, 463, 473, 479, 491, 521, 541, 557, 619, 643, 659 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..56.

Blair Kelly, Fibonacci and Lucas Factorizations.

FORMULA

{n: A038575(n)=3}. [R. J. Mathar, Jun 08 2010]

EXAMPLE

a(2)=15 because 15th fibonacci number(i.e. 610) consists of 3 prime factors (i.e. 2*5*61)

MATHEMATICA

t = {}; Do[f = FactorInteger[Fibonacci[n]]; If[Total[Transpose[f][[2]]] == 3, AppendTo[t, n]], {n, 2, 100}]; t (* T. D. Noe, Mar 14 2014 *)

Flatten[Position[Fibonacci[Range[700]], _?(PrimeOmega[#]==3&)]] (* Harvey P. Dale, Feb 15 2015 *)

PROG

(PARI) n=1; while(n<340, if(bigomega(fibonacci(n))==3, print1(n, ", ")); n++)

CROSSREFS

Cf. A072381, A114813.

Column k=3 of A303215.

Sequence in context: A199223 A199094 A009579 * A158338 A139204 A122661

Adjacent sequences:  A114809 A114810 A114811 * A114813 A114814 A114815

KEYWORD

nonn

AUTHOR

Shyam Sunder Gupta, Feb 19 2006

EXTENSIONS

More terms from Ryan Propper, May 22 2006

STATUS

approved

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Last modified July 22 16:43 EDT 2019. Contains 325225 sequences. (Running on oeis4.)