Question

A video game has been developed whereby the player must earn a certain number of experience points before progressing to the next level.

On level 1, a player must earn 1 experience point.
On level 2, a player must earn 7 experience points.
On level 3, a player must earn 15 experience points.
On level 4, a player must earn 25 experience points.

Which recursive equation represents the pattern?

an = an – 1 + n

an = an – 1 + 3n + 1

an = an – 1 + 5n

an = an – 1 + 2(n + 1)