172859domain: NPropertiesPrimalityPrimeyesAppears in sequencesNumber of nX3 0..1 arrays with every element equal to 0, 1, 2, 4, 5, 6 or 7 king-move adjacent elements, with upper left element zero.at n=10A299677Primes p such that there exists a prime q < p such that sigma(p-1) = sigma(q-1) = p + q.at n=5A385740Prime numbersat n=15743