Final answer:
A sequence that adds 7 between each index value is known as an arithmetic sequence, characterized by a constant difference of 7 between successive terms.
Step-by-step explanation:
If a sequence follows a pattern that adds 7 between each index value, then it must be an arithmetic sequence. In arithmetic sequences, the difference between successive terms is constant. For example, if we start with an initial term 'a', the sequence will be:
- a,
- a + 7,
- a + 14,
- a + 21,
- a + 28,
- and so on.
Each term is found by adding 7 to the previous term. This is commonly referred to as the common difference in an arithmetic sequence.