368280domain: NAppears in sequencesa(n) = 9*binomial(n,4) = 3*n*(n-1)*(n-2)*(n-3)/8.at n=33A060008Numbers m such that m^2 + (reversal of m)^2 is a square. (Leading 0's are ignored.)at n=4A068536Numbers n such that sigma(n) = 16*phi(n).at n=4A104903Numbers with prime factorization pqrs^3t^3.at n=27A190385