221953domain: NPropertiesPrimalityPrimeyesAppears in sequencesNumber of length n+2 0..2 arrays with the sum of second differences squared multiplied by some arrangement of +-1 equal to zero.at n=9A250314Primes of the form (2*p^2 + 1)/3 where p is a prime > 3.at n=30A362225Prime numbersat n=19772