173809domain: NAppears in sequencesSemiprimes whose prime factors are distinct and the reversal of one factor is equal to the other.at n=9A083815Expansion of (1+x)/(1-x^2-9*x^3).at n=16A097041Numbers k such that 2*10^k - 87 is prime.at n=30A273907Semiprimes whose prime factors are the digit reversal of each other.at n=23A376746