In this progression, each number after 1 is equal to the sum of the previous two numbers ​ — 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, and so on.
وهي تبدأ كالتالي :‏ ١ ،‏ ١ ،‏ ٢ ،‏ ٣ ،‏ ٥ ،‏ ٨ ،‏ ١٣ ،‏ ٢١ ،‏ ٣٤ ،‏ ٥٥ ،‏ وهكذا دواليك .‏