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A060320 Subscript of smallest Fibonacci number with n distinct prime factors. 4
1, 3, 8, 15, 20, 30, 40, 70, 60, 80, 90, 140, 176, 120, 168, 180, 324, 252, 240, 378, 450, 432, 552, 360, 420, 690, 504, 880, 630, 600, 756, 720, 900, 792, 840 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

LINKS

R. Knott, Fibonacci numbers with tables of F(0)-F(500)

Hisanori Mishima, Fibonacci numbers (n = 1 to 100)

Hisanori Mishima, Fibonacci numbers (n = 101 to 200)

Hisanori Mishima, Fibonacci numbers (n = 201 to 300)

Hisanori Mishima, Fibonacci numbers (n = 301 to 400)

Hisanori Mishima, Fibonacci numbers (n = 401 to 480)

FORMULA

a(n) = min (k : A022307(k) = n )

EXAMPLE

n=9: F(80)=23416728348467685=3 * 5 * 7 * 11 * 41 * 47 * 1601 * 3041 * 2161

n=25: F(690)=2^3 * 5 * 11 * 31 * 61 * 137 * 139 * 461 * 691 * 829 * 1151 * 1381 * 4831 * 5981 * 18077 * 28657 * 186301 * 324301 * 686551 * 1485571 * 4641631 * 117169733521 * 2441738887963981 * 3490125311294161 * 25013864044961447973152814604981 is the smallest Fibonacci number with 25 prime factors.

PROG

(PARI) for(n=1, 15, s=1; while(abs(omega(fibonacci(s))-n)>0, s++); print1(s, ", "))

CROSSREFS

Cf. A022307, A001605, A005478, A060319, A051694.

Sequence in context: A191773 A163603 A181027 * A162372 A101711 A048982

Adjacent sequences:  A060317 A060318 A060319 * A060321 A060322 A060323

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), Mar 28 2001

EXTENSIONS

Corrected by Shyam Sunder Gupta (guptass(AT)rediffmail.com), Jul 20 2002

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Last modified February 17 10:05 EST 2012. Contains 206009 sequences.