ClearAll[Lah] Lah[n_?Positive, 0] := 0 Lah[0, k_?Positive] := 0 Lah[n_, n_] := 1 Lah[n_, 1] := n! Lah[n_, k_] := (-1)^n (n! ((n - 1)!))/((k! ((k - 1)!)) ((n - k)!)) Table[Lah[i, j], {i, 0, 12}, {j, 0, 12}] // Grid Max[Lah[100, Range[0, 100]]]