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Old 2003-12-21, 21:10   #7
michael
 
Dec 2003
Belgium

1018 Posts
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721801 = 601x1201, that's already a little bigger, let's see if i can find some pseudoprimes to base 2,3,5,7 with only factors bigger than 7000...

Also:

A number n is a pseudoprime to the base b if b^n-1 is congruent to 1 modulo n.

A Carmichael number is a composite number n such that b^n-1 is congruent to 1 modulo n for every b that is relatively prime to n.

So we are talking about composite numbers that are pseudoprime to bases 2,3,5 and 7 ... this are not necessarily Carmichael numbers.

-michael
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