What is the term for a sequence where each term after the first is found by adding a constant to the previous term?

A sequence in which each term after the first is obtained by adding a fixed constant to the previous term is known as an arithmetic sequence. In this type of sequence, the difference between consecutive terms is constant; this difference is referred to as the common difference. For example, if the first term is 2 and the common difference is 3, the terms would be 2, 5, 8, 11, and so on, where each term increases by 3.

In contrast, a geometric sequence involves multiplying each term by a constant factor to obtain the next term, rather than adding. Harmonic sequences relate to the reciprocals of an arithmetic sequence, and Fibonacci sequences are generated by summing the two previous terms to get the next. Each of these other types of sequences has distinct rules governing how terms are generated, which is why they do not describe the process outlined in the question.