PRP Records

10^13661+21335779



10^n+21335779 searched up to n=28000.

The number 21335779 is a prime curiosity. Write down all the single-digit primes: 2 3 5 7. Then write the only digits a prime can end with: 1 3 7 9. Put the second set of digits between the first set like this: 2 (1) 3 (3) 5 (7) 7 (9) to get 21335779, which is prime.

PFGW Version 1.2.0 for Windows [FFT v23.8]

Primality testing 10^13661+21335779 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 2
Running N+1 test using discriminant 7, base 2+sqrt(7)
10^13661+21335779 is Fermat and Lucas PRP!

To be completed...




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