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[ November 11, 2006 ]
Two nice consecutive primes
by Farideh Firoozbakht (email)

I found two nice  consecutive  primes p & q
related to the palindromic number 1551.

p = n^n – (n – 1)  and  q = n^n + (n – 1)

or

p = 15511551 – (1551 – 1)  and  q = 15511551 + (1551 – 1)

or

p = 155115511550  and  q = 15511551 + 1550

The next term (q) of A058912 is thus 1551.


I sent a similar email to Giovanni Resta and
he checked the primality of p & q with pfgw.
He wrote: " They are very nice indeed !
It was so difficult to believe in such a coincidence,
with numbers of 4949 digits, that I must confess
that I checked them with pfgw !
"


A000169 Prime Curios! Prime Puzzle
Wikipedia 169 Le nombre 169














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