Final answer:
The expression 7n represents an arithmetic sequence with a common difference of 7, where each term is 7 times its position in the sequence.
Step-by-step explanation:
The expression 7n describes a sequence where each term is 7 times its position in that sequence. If n represents the position of the number in the sequence, and we substitute different values of n, the pattern can be seen clearly. For example, if n = 1, the term would be 7(1) = 7; if n = 2, the term would be 7(2) = 14, and so forth. This pattern produces a sequence of multiples of 7: 7, 14, 21, etc. Therefore, the pattern of numbers described by the expression 7n is known as an arithmetic sequence with a common difference of 7.