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%I #18 Nov 12 2019 04:18:56
%S 20,27,28,32,52,55,74,77,85,87,93,97,115,123,143,146,149,157,161,163,
%T 178,187,197,209,211,214,215,221,223,239,242,249,262,269,283,287,307,
%U 311,313,321,334,349,379,391,393,409,421,453,487,493,499,523,581,586
%N Indices of Fibonacci numbers with 4 prime factors when counted with multiplicity.
%C 1559, 1609, 2131, 2281, 2351, 2459, 2539, 3119, 3371, 4993, 5839, 6217, 7591, 7741, 8353, 9931 are also terms (data from Kelly link). - _Chai Wah Wu_, Nov 11 2019
%H Amiram Eldar, <a href="/A114813/b114813.txt">Table of n, a(n) for n = 1..86</a>
%H Blair Kelly, <a href="http://mersennus.net/fibonacci/">Fibonacci and Lucas Factorizations</a>.
%e a(1)=20 because 20th fibonacci number(i.e. 6765) consists of 4 prime factors (i.e. 3*5*11*41)
%t t = {}; Do[f = FactorInteger[Fibonacci[n]]; If[Total[Transpose[f][[2]]] == 4, AppendTo[t, n]], {n, 2, 100}]; t (* _T. D. Noe_, Mar 14 2014 *)
%o (PARI) n=1;while(n<340,if(bigomega(fibonacci(n))==4,print1(n,", "));n++)
%Y Column k=4 of A303215.
%K nonn
%O 1,1
%A _Shyam Sunder Gupta_, Feb 19 2006
%E More terms from _Ryan Propper_, May 22 2006
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