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 4 experience points.
On level 3, a player must earn 8 experience points.
On level 4, a player must earn 13 experience points.

Which recursive equation represents the pattern?

an = an – 1 + n

an = an – 1 + (n + 1)

an = an – 1 + 2n

an = an – 1 + (2n + 1)