$a_n = a_{n-1} + d$ for $n > 1$, with $a_1$

$a_n = d \cdot a_{n-1}$ for $n > 1$, with $a_1$

$a_n = a_{n-1} - d$ for $n > 1$, with $a_1$

$a_n = a_{n-1} \div d$ for $n > 1$, with $a_1$