1701630

Appears in sequences

• Triangular array read by rows: T(n,k) is the number of ways to partition an n-set into exactly k blocks and then partially order the blocks, n>=1, 1<=k<=n.at n=39A247231
• Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where column k is the expansion of B(x)^k, where B(x) is the g.f. of A381600.at n=52A381592
• G.f. A(x) satisfies A(x) = 1/(1 - x * A(x) * A(x*A(x)))^2.at n=7A381593