1841681domain: NPropertiesPrimalityPrimeyesAppears in sequencesNon-twin primes that are at least doubly lonely.at n=12A069456Ennea-Primes. Prime Numbers n (single prime number in-between 8 twin primes) such that Sum of 9 prime numbers (8 twin primes and single prime number in-between) are primes.at n=2A138399Prime numbersat n=137953