Answer:
aₙ = aₙ₋₁ + aₙ₋₂
where:
a₁ = 6
a₂= 1.
Explanation:
We have the sequence:
6, 1, 7, 8, 15, 23, ...
Is easy to see that this sequence works as follows:
You take 2 consecutive numbers, and the next number is the sum of these two.
Then we have:
6 + 1 = 7
1 + 7 = 8
7 + 8 = 15
8 + 15 = 23
Then the n-th term is equal to the sum of the (n - 1) term and the (n - 2) term.
This is written as:
aₙ = aₙ₋₁ + aₙ₋₂
Because in the recursive rule needs two previous terms, we need to specify the two first terms of the sequence.
Then we need to write also:
a₁ = 6
a₂= 1.