1624350domain: 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=4A118859(Denominators of Cauchy numbers of the first kind c_{2n})/6.at n=23A222560(Denominators of Cauchy numbers of the second kind hat c_{2n})/6.at n=23A222561