21968100domain: NAppears in sequencesNumbers k such that k-1, k+1, 2*k-1, 2*k+1, 3*k-1 and 3*k+1 are primes.at n=22A118859Numbers k such that k-1, k+1, 2k-1, 2k+1, 3k-1, 3k+1, 4k-1 and 4k+1 are all primes.at n=0A118860Smallest k such that the numbers j*k - 1 and j*k + 1 are prime for 1 <= j <= n.at n=3A348348