570569

Properties

Appears in sequences

• Smallest prime p such that p+1 is the product of exactly n distinct prime numbers.at n=6A098026
• Prime numbers appearing in A139033.at n=17A139034
• Sophie Germain primes that are also highly cototient numbers.at n=30A209194
• a(n) is the smallest number k such that psi(k) = A001615(k) is the product of n distinct primes.at n=6A291144
• Numbers k such that phi(sigma(k))/k < phi(sigma(m))/m for all m < k, where sigma is the sum of divisors function (A000203) and phi is Euler's totient function (A000010).at n=39A293711
• Numbers k such that phi(psi(k))/k < phi(psi(m))/m for all m < k, where phi is Euler's totient function (A000010) and psi is the Dedekind psi function (A001615).at n=41A293713
• Numbers k where records occur for phi(k)/phi(k+1), where phi is the Euler totient function (A000010).at n=35A335070
• a(n) is the least k for which omega(k)*omega(k + 1) = n where omega = A001221.at n=7A391216
• a(n) is the least k for which omega(k)*omega(k + 1)*omega(k + 2) = n where omega = A001221, or -1 if no such k exists.at n=14A392184
• Prime numbersat n=46870