2550183799domain: NAppears in sequencesSmallest prime factor of Mersenne numbers 2^p-1, where p is prime.at n=26A016047Smallest prime factor of composite Mersenne numbers: lpf(2^p-1) where 2^p-1 is composite and p is prime.at n=16A136030a(n) is the least prime factor (> 3) in the factorization of 2^(2*prime(n))-1.at n=26A363673