49301domain: NAppears in sequencesIndices of triple-safe primes: p=prime(n) is double-safe: q=(p-1)/2, r=(q-1)/2 and s=(r-1)/2 are all prime (and q is double-safe).at n=33A075134Number of length 1+3 0..n arrays with some pair in every consecutive four terms totalling exactly n.at n=19A245951