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>I am new to this file and I need help from the mathematicians. I was interested
>in finding the largest n digit prime number. I am using the formula :
>
> n
> 10 - 3, where n is a positive integer
>
I am not a mathematician, but if you consider the sequence of n-digit numbers
of the form
S(n) = 10^n - 3
it is interesting to note that S(1), S(2), S(3), and S(17) are prime.
One might conjecture that
(1) there are an infinite number of S(n) which are prime.
(2) a necessary condition for S(n) prime is n to be prime.
There is no other prime S(n) for n<140. But S(140) seems to be prime.
So strike conjecture 2. Are there an infinite number of S(n) prime?
I believe the most I can offer to answer _your_ question is that the largest
n-digit prime for a given n probably starts with one or more 9's and ends with
1, 3, 7, or 9. Maybe someone else can define this more tightly.
Allen
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