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Old 2007-01-25, 12:35   #9
robert44444uk
 
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Jun 2003
Oxford, UK

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Quote:
Originally Posted by Citrix View Post
Found another lowest number =1307. 512 is a trivial solution, this is not.

Will continue to prove 1307 is the smallest such number.

Have not found a -1 number upto 250,000. Not sure if there is one. may be the same covering set as +1 can be used. Need help here, if anyone can offer.
Citrix, what is yor covering set for 1307? Obvioulsy there are not many n for which small factors cannot be found but there are 708 n values in the first 100,000 n which have no factors smaller than 50 million.

For example, my NewPgen file reads (for the "Sierpinski":

51763650:P:0:1307:257
2 123
2 387
2 435
2 723
2 891
2 1131
2 1155
2 1443
2 1491
2 1515
2 1803
2 1947
2 1971
2 1995.....

None of these are prime up to n=4731

Last fiddled with by robert44444uk on 2007-01-25 at 12:36
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