WINning formula

A formula I derived myself.
If I know the total number of participants, n.

n is the total number of participants
n(n/2-1)+n/2+n, where n>2
if n=10
10(10/2-1)+10/2+10
10(5-1)+5+10
10(4)+15
answer: 55

Applications:
If I organize a concert, the entry fee starts from RM1.
The next person who buys the ticket will have to pay an additional RM1.
1st person pays: RM1
2nd person pays: RM2
3rd person pays: RM3

Total revenue
=n(n/2-1)+n/2+n, where n=3
=6

In Microsoft Excel, it is
=C1*((C1/2)-1)+(C1/2)+(C1) assuming C1 contains the total number of participants