446369domain: NAppears in sequencesa(n)=(n^4-n^3-n^2-n)/2.at n=31A171129Numbers such that the minimum distance between divisors of n occurs only between composite numbers.at n=21A253266Numbers x whose 10's complements y have the same sum of divisors of x, with x <> y.at n=30A300796Positions of 3's in A347381.at n=29A347393