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Strange behaviour of prime numbers
05-20-2019, 04:34 PM (This post was last modified: 05-27-2019 08:59 AM by fred_76.)
Post: #1
Strange behaviour of prime numbers
Hello

I found a strange behaviour in the prime numbers.

About 33.8% of the prime numbers ending by 9 are followed by a prime number ending by 1. On the contrary, only about 15.9% of the prime numbers ending by 3 are followed by a prime number ending by 3 (the same applies with 7 followed by 7 with 15.8%).

The table is as followed :
ending by, followed by, % vs primes endind by
1, 1, 17.1%
1, 3, 31.0%
1, 7, 31.8%
1, 9, 20.1%

3, 1, 23.3%
3, 3, 15.9%
3, 7, 29.1%
3, 9, 31.7%

7, 1, 25.7%
7, 3, 27.4%
7, 7, 15.8%
7, 9, 31.0%

9, 1, 33.8%
9, 3, 25.8%
9, 7, 23.3%
9, 9, 17.1%

Therefore, if you search for a prime number following another one, use this table to maximize your chances.

—- edit —-
Change % to the « primes ending by » instead of to the « total nb of primes ».
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Strange behaviour of prime numbers - fred_76 - 05-20-2019 04:34 PM



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