240492

Appears in sequences

• a(n) = Sum_{k=0..n} C((n-k)*k, k) * C((n-k)*k, n-k).at n=7A137645
• G.f.: exp( Sum_{n>=1} (x^n/n) * Product_{d|n} (1 + n*x^d/d) ).at n=33A205476