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A114843 Indices of Fibonacci numbers with 4 distinct prime factors. 2

%I #13 Oct 14 2019 06:54:12

%S 20,24,27,28,32,52,55,74,77,85,87,91,93,97,115,123,143,146,149,157,

%T 161,163,178,187,197,209,211,214,215,221,223,239,242,249,262,269,283,

%U 287,307,311,313,321,334,349,379,391,393,409,421,453,487,493,499,523,581,586,617,641,647,677,691,707,709,787,794,811,823,839,853,859,887,907,913,929,941,953,1031,1049,1063,1093,1229

%N Indices of Fibonacci numbers with 4 distinct prime factors.

%H Amiram Eldar, <a href="/A114843/b114843.txt">Table of n, a(n) for n = 1..88</a>

%H Blair Kelly, <a href="http://mersennus.net/fibonacci/">Fibonacci and Lucas Factorizations</a>.

%e a(1)=20 because 20th fibonacci number consists of 4 distinct prime factors (i.e. 6765 = 3 x 5 x 11 x 41)

%o (PARI) n=1;while(n<350,if(omega(fibonacci(n))==4,print1(n,", "));n++)

%Y Cf. A114823-A114826, A114836-A114841.

%Y Column k=4 of A303217.

%K nonn

%O 1,1

%A _Shyam Sunder Gupta_, Feb 19 2006

%E More terms from _Ryan Propper_, Apr 26 2006

%E a(56)-a(81) from _Max Alekseyev_, Aug 18 2013

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Last modified March 29 09:44 EDT 2024. Contains 371268 sequences. (Running on oeis4.)