Another option is to use Pivot Table.
No formulas are required.
The table will look like this:
Count of ProjID ProjID
AccID 0 50 200 300 500
3010 1
3011 1 1
4010 1
5050 1
6010 1 1

A few more keystrokes will format it like this:
3010
3011 200 300
4010 50
5050
6010 300 500