720259

Appears in sequences

• E.g.f.: exp(x + 4*x^2 + 9*x^3).at n=7A293721
• Square array A(n,k), n >= 0, k >= 1, read by antidiagonals, where column k is the expansion of e.g.f. exp(Sum_{j=1..k} j^2*x^j).at n=52A293724