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 2005-10-11, 00:39 #1 meeztamike   Oct 2005 416 Posts I am sorry please read this I am sorry I made a mistake. I told you the numbers were 11,13,17,19 and they are 13,15,17,19 I wrote last night half asleep and did not look at my notes. I agree that I am not as smart as you all but give me a little credit for tring. please do the math again and let me know if there is anything here,I can take it if I am wrong no need to get nasty. I just need a little help. The formula for the first 20 is if the sum ends with a 2 you minus 13, if it ends with a 4 you minus 15, if it ends with a 6 you minus 17, and if it ends with a 8 you minus19. Last fiddled with by meeztamike on 2005-10-11 at 00:43
 2005-10-11, 20:36 #2 ewmayer ∂2ω=0     Sep 2002 República de California 2·4,919 Posts There was no need to start a new thread for this - you could've just followed the redirect link to your original thread (moved to the math section, which is more appropriate for it) and posted there. I've moved this thread there, as well. Anyway, your latest set of supposedly magic pattern numbers fares even worse than the first: The smallest value of n that makes all of 2^n-{13,15,17,19} positive is n=5. For this smallest n-value, 2^n-17 = 15, which is not prime. For n=6, just one of the numbers of the resulting quartet is prime. Have you even considered trying to learn the teensiest bit of number theory?
 2005-10-11, 22:13 #3 ewmayer ∂2ω=0     Sep 2002 República de California 2×4,919 Posts Oh, and for 2^n-{13,15,17,19}, the first value of n for which none of the quartet is prime is 25. Similarly for n=26,27,28,29,30,33,34,35,37,38,40,41,.... But I'm sure you'll manage to discern yet another mystical "pattern" in that. ("Oh - look! One of the four numbers is prime for n=31 - that's a Mersenne prime, and a Mersenne prime exponent at the same time. Amazing! And 32 - that's a power of 2! And 36 - my Mom's shoe size in European units! Holy cow!") One can spend one's entire life coming up with ever-fancier constructions like this, which basically amount to ways of a priori eliminating small divisors as candidates. Whoop dee doo - these *never* hold up for arbitrarily large numbers. I'd refer you to any of several good links on prime-generating polynomials by way of example, but that would require you to do actual reading, which is, like, work and stuff. Last fiddled with by ewmayer on 2005-10-11 at 22:13
 2006-01-03, 01:47 #4 jasong     "Jason Goatcher" Mar 2005 5·701 Posts I did a search on "prime generating formula" and I found the following website: http://mathworld.wolfram.com/Prime-G...olynomial.html Amazing stuff!!!

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