(a(i))[1]
In the first sequence, each term is $2$ greater than the one before it. Find an expression, in terms of $n$, for the $n$th term.
(a(ii))[1]
The $k$th term of this sequence is $841$. Find the value of $k$.
(b(i))[1]
The $n$th term of the second sequence is $2^{n-1} - \dfrac{(n-1)(n-4)}{2}$. Find the fourth term of this sequence.
(b(ii))[1]
Find the fifth term of this sequence.