48616domain: NAppears in sequencesNumbers k such that sigma(k) = phi(k+1) + phi(k) + phi(k-1).at n=19A065986Numbers whose square is the product of a number and its reverse.at n=21A207373Non-palindromes numbers not ending in 0 whose square is the product of a number and its reverse in only one way.at n=12A325151