20427264

Appears in sequences

• Numbers k such that sigma(k) = 7k/2.at n=3A055153
• Numbers m with half-integral abundancy index, sigma(m)/m = k+1/2 with integer k.at n=7A159907
• Numbers n such that gcd(sigma(n), n) > gcd(sigma(m), m) for all m < n.at n=22A216793
• Numbers n with the property that, if tau(n) = k = number of divisors of n, and the d(i) are the divisors [arranged in increasing order], then the sum 1/d(k) + 1/d(k-1) + 1/d(k-2) + ... + 1/d(q) is an integer for some q.at n=24A226476
• Numbers n such that antisigma(n) mod n = 0, where antisigma(n) = A024816(n) = sum of numbers less than n which do not divide n.at n=8A242484
• Numbers k that divide 2*sigma(k).at n=18A246454
• Integers m such that the sum of the first k divisors is equal to 2*m for some k less than the number of divisors of m.at n=6A306373
• Number of unordered pairs of self-avoiding paths with nodes that cover all vertices of a convex n-gon.at n=12A332426