Sequences

A sequence is an ordered list of terms following a rule.

Linear (arithmetic) sequences

The difference between terms is constant ($d$). The $n$th term is: $$\text{nth term} = dn + (a_1 - d)$$ In practice: the coefficient of $n$ is the common difference; adjust the constant to match the first term. E.g. 5, 8, 11, 14…: difference 3, so $3n+2$.