2988119207domain: NAppears in sequencesa(n) is the smallest prime p such that p, p+d, and p+2d are consecutive primes where d = 2 for n = 1 and d = 6*(n-1) for n > 1.at n=22A052187First of three consecutive primes in arithmetic progression with gap of 6n, and such that a(n) > a(n-1).at n=21A224325