4444747domain: NPropertiesPrimalityPrimeyesAppears in sequencesPrimes that contain digits 4 and 7 only.at n=10A020465Smallest n-digit prime containing only the digits 4 and 7, or 0 if no such prime exists.at n=6A036944Primes of the form 3x^3+x+1.at n=20A114351Prime numbersat n=312316