281600

Appears in sequences

• Glaisher's function theta(n) (18 squares version).at n=8A002614
• Numbers that can be written as k/d(k) in four or more ways, where d(k) = number of divisors of k.at n=29A051346
• A unitary phi reciprocal amicable number: consider two different numbers r, s which satisfy the following equation for some integer k: uphi(r) = uphi(s) = (1/k) * r * s / (r-s); or equivalently, 1/uphi(r) = 1/uphi(s) = k * (1/s - 1/r); sequence gives s numbers.at n=24A080767
• a(n) is the smallest number m such that sigma(m)=n*pi(m), or 0 if no such m exists.at n=29A137602
• a(n) = 16*a(n-1) - 56*a(n-2) for n>1, with a(0)=1, a(1)=16.at n=5A154348
• Numbers n such that n = k/d(k) has exactly 4 solutions, where d(k) = number of divisors of k.at n=27A217125
• a(n) = Sum_{0 < x,y,z <= n and gcd(x^2 + y^2 + z^2, n)=1} gcd(x^2 + y^2 + z^2 - 1, n).at n=39A239612
• Binomial transform of the sum of the first n even squares (A002492).at n=10A240434
• a(n) = n^5 * Sum_{p|n, p prime} 1/p^5.at n=23A351245
• a(n) = 2^(n-6)*n*(n^3 - 6*n^2 + 19*n - 14).at n=11A384243