1098720

Appears in sequences

• The number of unordered pairs (f,g) of functions from {1..n} to itself such that fg=gf (i.e., f(g(i))=g(f(i)) for all i) where f and g are distinct.at n=5A254570
• Numbers n such that sigma(sigma(n))/sigma(n) > sigma(sigma(m))/sigma(m) for all m < n.at n=36A289124