224450

Appears in sequences

• Numbers k such that the harmonic mean of the divisors of k is the square of a rational number.at n=26A074266
• Numbers of the form 2*k^2 such that sigma(2*k^2) is an odd square.at n=1A074388
• Numbers n such that both sigma(n) and sigma(sigma(n)) are odd numbers.at n=5A097025
• Numbers k such that squarefree part of sigma(k) is equal to squarefree part of 2*k.at n=27A331752
• For 1<=x<=n, 1<=y<=n, write gcd(x,y) = u*x+v*y with u,v minimal; a(n) = n^4*s, where s is the population variance of the values of v.at n=14A345688