Question

How do you find the explicit formula for the following sequence 7, 15, 23, 31, 39,...?

Answer 1

`7 = 7\times1+0; \qquad 15 = 7\times2+1; \qquad 23 = 7\times3+2;`
`31 = 7\times4 + 3; \qquad 39 = 7\times5 + 4`.
By induction, the `n`'th term must be : `7n+(n-1)`

Explanation:

No explanation needed ...