The Rule for an Arithmetic Sequence: an = a1 + (n – 1)d. an is the nth term of the sequence. a1 is the first term of the sequence. n is the number of terms in the sequence. d is the common difference.

What is an in arithmetic sequence?

An arithmetic sequence (also known as an arithmetic progression) is a sequence of numbers in which the difference between consecutive terms is always the same. For example, in the arithmetic sequence 1, 5, 9, 13, 17, …, the difference is always 4. This is called the common difference.

What is the rule of each sequence?

Number sequences are sets of numbers that follow a pattern or a rule. If the rule is to add or subtract a number each time, it is called an arithmetic sequence. If the rule is to multiply or divide by a number each time, it is called a geometric sequence. Each number in a sequence is called a term.