Generalized Fermat Primes, 20
Term: b1048576 + 1
Total: 6
References: PrimePages
Rank Number Digits When Who PrimePages - ID
1 53362841048576 + 1 7054022 Nov 2025 Antonio Lucendo; GFNSvCUDA sieve; GeneFer; AthGFNSieve; PrimeGrid; LLR 141212
2 38432361048576 + 1 6904556 Dec 2024 Jonas Skendelis; GFNSvCUDA sieve; GeneFer; AthGFNSieve; PrimeGrid; LLR 138793
3 19637361048576 + 1 6598776 Sep 2022 Tom Greer; GFNSvCUDA sieve; GeneFer; AthGFNSieve; PrimeGrid; LLR 134423
4 19517341048576 + 1 6595985 Aug 2022 Kazuya Tanaka; GFNSvCUDA sieve; GeneFer; AthGFNSieve; PrimeGrid; LLR 134298
5 10590941048576 + 1 6317602 Nov 2018 Rob Gahan; GFNSvCUDA sieve; GeneFer; AthGFNSieve; PrimeGrid; LLR 125753
6 9194441048576 + 1 6253210 Sep 2017 Sylvanus A. Zimmerman; GFNSvCUDA sieve; GeneFer; AthGFNSieve; PrimeGrid; LLR 123875

Generalized Fermat Primes, 21
Term: b2097152 + 1
Total: 1
References: PrimePages
Rank Number Digits When Who PrimePages - ID
1 25241902097152 + 1 13426224 Oct 2025 Tom Greer; GFNSvCUDA sieve; GeneFer; AthGFNSieve; PrimeGrid; LLR 141162