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.
Selles progressioonis on iga pärast numbrit 1 järgnev arv võrdne eelmise kahe numbri summaga: 1, 1, 2, 3, 5, 8, 13, 21, 34, 55 ja nii edasi.