75161927681domain: NAppears in sequencesSmallest prime of form 2^n*k + 1.at n=31A035089a(n) is the least prime p such that p-1 is divisible by 2^n and not by 2^(n+1).at n=31A057775Primes p such that valuation(p-1,2) is a record.at n=20A370606