75031250

Appears in sequences

• Numbers k such that sigma(k) + tau(k) is a prime.at n=19A064205
• Numbers k such that sigma(k) - tau(k) is a prime.at n=22A065061
• Numbers k such that sigma(k) + tau(k) and sigma(k) - tau(k) are primes.at n=10A065116
• Nonsquare numbers k such that the denominator of the harmonic mean of the divisors of k is larger than 2*k.at n=15A348827
• Nonsquare numbers k such that tau(sigma(tau(k))) = sigma(tau(sigma(k))), where tau is A000005 and sigma is A000203.at n=3A355707