Rectangular array read by antidiagonals: a(n, k) is the number of ways to put k labeled objects into n labeled boxes so that there are exactly two boxes with exactly one object (n, k >= 2).

A131105

Rectangular array read by antidiagonals: a(n, k) is the number of ways to put k labeled objects into n labeled boxes so that there are exactly two boxes with exactly one object (n, k >= 2).