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

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 : $7 n + \left(n - 1\right)$