olemus
algarv p, mille korral ka 2p+1 on algarv,
näiteks
2, 3, 5, 11, 23, 29, 41, 53, 83, 89, 113, 131, 173, 179

Wiktionary:
any prime number p where 2p + 1 is also prime

ülevaateid
https://mathworld.wolfram.com/SophieGermainPrime.html

https://en.wikipedia.org/wiki/Safe_and_Sophie_Germain_primes

https://www.ams.org/journals/mcom/1996-65-213/S0025-5718-96-00670-9/S0025-5718-96-00670-9.pdf

https://prime-numbers.info/list/sophie-germain-primes