480200

Appears in sequences

• Initial values for f(x)=phi(sigma(x)) such that iteration of f ends in cycle of length=15.at n=1A096889
• a(n) is the smallest number satisfying a(n)^2+1 = p(n)*q(n), p(n) < q(n) both prime, such that q(n+1)/p(n+1) < q(n)/p(n) with the initial condition q(1)/p(1) < 3/2.at n=22A261803
• Numbers m such that m^2 + 1 = p*q with p, q primes and m = (p + q)/2 - 1.at n=18A348594