Palindromic Primes: Find A from 1000-2000

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In summary, a palindromic prime is a number that is both a prime number and a palindrome. To find palindromic primes between a range of numbers, we can use a combination of finding all prime numbers in the range and checking if they are also palindromes. These numbers have significance in number theory and cryptography and can be used in creating secure codes and passwords. There is no known pattern or formula for generating palindromic primes, and the largest known one as of 2021 is 998,001 digits long.
  • #1
Albert1
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given : A=B$\times $C
with the following characters
(1) A,B,C $\in N$
(2)A is a palindrome
(3)B and C are all palindromic primes
(4) 1000<A<2000
(5) B is a 2-digit number
(6) C is a 3-digit number
find A
 
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  • #2
Albert:

[sp]If A is the product of B and C how can A be prime?[/sp]
 
  • #3
greg1313 said:
Albert:

[sp]If A is the product of B and C how can A be prime?[/sp]
sorry! A is a palindrome but not a prime
 
  • #4
only 2 digit palinodromic prime is B = 11
A < 2000 and is of the form 1aa1
from this and C is palinodrom and prime we have C < 2000/11 and C >=100 hence C = 101 or 131 or 151 or 181
giving A = 1111, 1441, 1661, 1881

so we have following combinations (1111 = 1 1 * 101, 1441 = 11 * 131, 1661 = 11 * 151, 1991 = 11 * 181
 

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