152670domain: NAppears in sequencesRestricted partitions.at n=23A002574Numbers with exactly 5 distinct prime factors each of which is a palindrome.at n=32A046403Numbers k such that 2*10^k + 4*R_k - 1 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=19A102953