520193domain: NPropertiesPrimalityPrimeyesAppears in sequencesPrimes p such that cototient(totient(p)) = A070556(p) is a power of 2.at n=17A070806Primes of the form 2^j - 2^k + 1, where j > k >= 0.at n=40A152449Primes of the form q*2^h + 1, where q is a Mersenne prime.at n=12A336117Prime numbersat n=43074