Sequences (Edexcel IGCSE Maths A: Foundation): Exam Questions

Here are the first five terms of a number sequence.

7 11 15 19 23

Find an expression, in terms of , for the th term of this sequence.

The th term of a different number sequence is given by

Write down the first 3 terms of this sequence

Yuen says there are no numbers that are in both of the sequences.
Yuen is correct.

Explain why.