# Math Help - Sequences

1. ## Sequences

Hi Guys, I desperately need to know if there is a simple formula for the following set of numbers.
3
7
12
18
25
33
42 etc

You can see that the number by which it increses is 1 extra each time but I need to know how to but this into a formula.

Thanks,

Mark

2. Originally Posted by Berwick
Hi Guys, I desperately need to know if there is a simple formula for the following set of numbers.
3
7
12
18
25
33
42 etc
$\frac{n(n+5)}{2}$