22253377

Properties

Appears in sequences

• Largest prime factor of 16^n + 1.at n=12A002590
• For p = prime(n), a(n) is the largest prime q such that pq is a base-2 pseudoprime; that is, 2^(pq-1) = 1 mod pq; a(n) is 0 if no such prime exists.at n=23A086019
• Numbers k (between 2^(m-1) and 2^m) such that 2^(k-1) == 1 (mod k) and 2^(k-1-m) == k - 2^p (mod k) for some p > 0 with 2^p < k.at n=38A167612
• Start with 7; thereafter, in order of appearance, the prime factors of A220294.at n=7A255772
• Largest prime factor of 4^n + 1.at n=24A274903
• Largest prime factor of 8^n + 1.at n=16A274905
• Largest prime factor of 8^n - 1.at n=31A274908
• Prime factors of numbers of the form 4^(2^m) - 2^(2^m) + 1 with m >= 0.at n=9A275528
• a(n) = largest prime q such that q | 2^p - 2 and p - 1 | q - 1, where p = prime(n).at n=24A287945
• a(n) is the largest prime factor of 2^(prime(n) - 1) - 1.at n=23A358699
• Anti-elite primes (A128852) that are not prime factors of Fermat primes (A023394).at n=31A372891
• Prime numbersat n=1404142