4580064

Appears in sequences

• Unitary superperfect numbers: numbers n such that usigma(usigma(n)) = 2*n, where usigma(n) is the sum of unitary divisors of n (A034448).at n=20A038843
• G.f. A(x) satisfies: 1 = Sum_{n>=0} (-x)^n * A(x)^(2*n) * A(x*A(x)^n).at n=11A352854