20180102, 18:30  #12  
Aug 2006
2^{2}·5·293 Posts 
Quote:


20180103, 01:53  #13  
Romulan Interpreter
Jun 2011
Thailand
10000101011111_{2} Posts 
Quote:
This will record the found terms, so they do not get lost, and not only will mark the fact that some unknown terms may lay in between, but will also tickle the reader's curiosity so they will want to investigate the gaps and who knows? maybe fill them in, or eliminate the doubt... 

20180103, 02:01  #14  
"Forget I exist"
Jul 2009
Dumbassville
20300_{8} Posts 
Quote:


20180103, 03:28  #15  
Dec 2017
2×5^{2} Posts 
Quote:


20180103, 04:24  #16 
Aug 2006
2^{2}×5×293 Posts 

20180103, 06:14  #17  
Dec 2017
62_{8} Posts 
Quote:
From this, could we perhaps raise an upper bound on n? For instance, is there a way of mathematically showing the largest value of n < k such that F(n) is prime? I have made an attempt of trying to look at a pattern of the last digits of the fibonnaci numbers. Of course, if they are odd, then the fibonnaci number with that odd last digit stands a chance of being prime. Through my work, I noticed that the final digits of the fibonnaci sequence have a cycle length of 60. For example, the first few fibonnaci numbers in the sequence are 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, … So the sequence of the last digits would be in this case 1, 1, 2, 3, 5, 8, 3, 1, 4, 5, 9. But why must this sequence have a cycle length of 60? Well, 60 is the smallest number to be divisible by all the numbers from 1 to 6 (it is a weak factorial of 6) and the first 6 fibonnaci numbers represent its own last digit... hmmm... maybe that’s the reason? Any suggestions? Last fiddled with by George M on 20180103 at 06:15 Reason: Improved punctuation and grammar. 

20180103, 06:31  #18 
"Serge"
Mar 2008
Phi(3,3^1118781+1)/3
2^{2}×37×61 Posts 

20180103, 06:36  #19  
Dec 2017
2×5^{2} Posts 
Quote:
https://m.youtube.com/watch?v=NulWIfyec Thank you for showing me that link :) 

20180103, 07:37  #20  
Jun 2003
3·1,531 Posts 
Quote:


20180103, 16:04  #21  
Aug 2006
2^{2}×5×293 Posts 
Quote:


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