9904204800domain: NAppears in sequencesNumbers k for which sigma(k)/k - 3/7 is an integer.at n=10A218410Numbers k for which k * gcd(sigma(k), u) is equal to sigma(k) * gcd(k, u), where u is obtained by shifting the prime factorization of k two steps toward larger primes [with u = A003961(A003961(k))].at n=20A349746