391151domain: NPropertiesPrimalityPrimeyesAppears in sequencesLargest prime factor of 3^(2n+1) - 1.at n=12A002591Largest prime factor of 3^n - 1.at n=24A074477List of primitive prime divisors of the numbers (3^k-1)/2 (A003462) for k>=2, in order of their occurrence.at n=31A129733Prime numbersat n=33161