Question

Write the formula for the sequence below:

13, 20, 27, 34, ...

Answer 1

aₙ = 6 + 7n

Explanation:

20 - 13 = 27 - 20 = 34 - 27 = 7

It is an arithmetic sequence with common difference of 7

a₁ = 13

a₂ = 20 = 13 + (2 -1 )*7

a₃ = 27 = 13 + (3 - 1)*7

a₄ = 34 = 13 + (4 - 1)*7

...

aₙ = 13 + (n - 1)*7 = 13 + 7n - 7 = 6 + 7n

ao

aₙ = 6 + 7n