Lucas numbers are a sequence of numbers similar to the Fibonacci sequence. They start with 2 and 1, and each subsequent number is the sum of the two preceding ones. The sequence begins as 2, 1, 3, 4, 7, 11, 18, and so on. The n-th Lucas number can be expressed mathematically as L(n) = L(n-1) + L(n-2) , where L(0) = 2 and L(1) = 1 . Lucas numbers have various applications in mathematics, including number theory and combinatorics, and they share many properties with the Fibonacci numbers.