OFFSET
1,1
COMMENTS
A072381 is subsequence, since the only square Fibonacci numbers are 1 and 144 which are not squares of primes. - Charles R Greathouse IV, Sep 24 2012
LINKS
Yann Bugeaud, Florian Luca, Maurice Mignotte, and Samir Siksek, On Fibonacci numbers with few prime divisors, Proc. Japan Acad. Ser. A Math. Sci., Volume 81, Number 2 (2005), 17-20.
EXAMPLE
a(1) = 8 because 8th Fibonacci number consists of 2 distinct prime factors (i.e. 21 = 3*7).
25 is in the sequence because Fibonacci(25) = 75025 = 5^2 * 3001 consists of 2 distinct prime factors.
PROG
(PARI) n=1; while(n<355, if(omega(fibonacci(n))==2, print1(n, ", ")); n++)
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
Shyam Sunder Gupta, Feb 19 2006
EXTENSIONS
a(40)-a(50) from Donovan Johnson, Sep 27 2008
a(51)-a(52) from Max Alekseyev, Aug 18 2013
a(53) from Amiram Eldar, Oct 14 2019
STATUS
approved