T(0) = 1, T(1) = 1, T(n) = 1 + (n - 1) (1 + (n - 2) + T(n - 1) + subfactorial(n - 1) n + (n - 2) + T(n - 2) + subfactorial(n - 2) (n - 1))

• Lenguaje natural
• Entrada matemática