**Helpful Links**Question**

14) Here are the first four terms of a sequence.

a) Write down the next term.

**[1 mark]**

b) Write an expression for the

*n*th term.

**[2 marks]**

c) Explain why 511 is

**not**a term in the sequence.**[1 mark]**

d) Find the term in the sequence that is nearest to 511.

**[3 marks]**