Akademik

(mathematics) a progression in which a constant is added to each term in order to obtain the next term

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1-4-7-10-13- is the start of an arithmetic progression

arithˌmetic proˈgression [arithmetic progression] (also arithˌmetic ˈseries) noun

a series of numbers that decrease or increase by the same amount each time, for example 2, 4, 6, 8

compare ↑geometric progression