A playground is being designed where children can interact with their friends in certain combinations. If there is 1 child, there can be o interactions.
If there are 2 children, there can be only 1 interaction.
If there are 3 children, there can be 4 interactions.
If there are 4 children, there can be 9 interactions.
Which recursive equation represents the pattern?
an-an-1 +31 - 2
an-an-+ 21 - 3
an = an- 1 + (3n - 2)
an = an- 1 + (2n-3)