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Pastimes : My House -- Ignore unavailable to you. Want to Upgrade?

To: Lazarus_Long who wrote (4553)	1/23/2003 8:21:43 PM
From: TimF	Read Replies (1) \| Respond to of 7689

Well it wasn't too easy. I almost gave up on it until I started to think "outside the box". The natural tendency is to think about just transporting things over and never taking anything back but there is no way to do that and not have something eaten... And if you enough math, you may be able to answer that immediately. If I'm enough math? I think I could give you an answer but only by plugging lots of solutions in to the problem until either I found one that was not prime or gave up and figured that F(x) was prime for any integer x. I just thought of something. You didn't say positive integers. F(-1) is 41, F(-2) is 43, F(-3) is 47 F(-4) is 53, F(-5) is 61, F(-6) is 71, F(-7) is 83. Hmm it seems to be following the same pattern once you get past F(-1). F(-x) = F(x-1) Hmm. I could cheat. If this is a famous problem I could probably find it on an internet search and you would never know if it wasn't for the fact that I am posting stream of consciousness here... :) BTW I didn't cheat on the last one. I almost did but I decided to give it one more try and that try worked. Well it comes down to I don't know the answer. I would try the "brute force" method of solving for a bunch of different X's but I don't know a quick way to figure out if a number is prime. Tim