13045131

Appears in sequences

• Denominator of sum of -5th powers of divisors of n.at n=32A017674
• Numbers n such that (phi(n) + sigma(n))/(rad(n))^2 is an integer > 1 (phi=A000010, sigma=A000203, rad=A007947).at n=27A097982
• Numbers of the form (9^i)*(11^j), with i, j >= 0.at n=33A108687
• Numbers k such that (phi(k) + sigma(k))/rad(k)^2 is an integer, that is (phi(k) + sigma(k)) is divisible by every prime factor of k squared.at n=29A121850
• Numbers of the form p^4*q^5 where p and q are two distinct primes.at n=21A179702