Question

Write an explicit formula for the sequence 4, 7, 10, 13, 16,

Answer 1

The common difference is 3, so, a formula can be:

\(\Large \color{midnightblue}{\rightarrow n_{t} = 1 + 3n }\)

Answer 2

The formula is actually:
\(\Large \color{midnightblue}{\rightarrow 4 + 3(n - 1) }\)
But, simplifying:
\(\Large \color{midnightblue}{\rightarrow 4 + 3n - 3}\)
\(\Large \color{midnightblue}{\rightarrow 1 + 3n }\)