85880domain: NAppears in sequencesNumbers n such that n is a substring of its square in base 7 (written in base 10).at n=16A018831Numbers k such that k*Sum_{d|k} 1/sigma(d) is an integer.at n=30A069166a(n) = Sum_{k=0..n} r_4(k^2 + 1), where r_4(k) is the number of ways of writing k as a sum of 4 squares (A000118).at n=28A333174