54254domain: NAppears in sequencesSecond (lower) diagonal of partition triangle A047812.at n=18A007045Partial sums of round(5^n/9).at n=8A178577Least positive integer m with prime(m)+2 and prime(prime(m))+2 both prime such that prime(m*n)+2 and prime(prime(m*n))+2 are both prime.at n=56A259487