How to generate alphanumeric project number automatically based on certain logic?

Dear Experts,

We want to generate project number Alphanumeric based on our logic as below:

total chars allowed in proj number are: 17

First 4 - company code
Next 4 - year of proj request
etc logic we have to comeup with total 17 chars proj number. this is been manual so far. We want to automate it.

How to generate alphanumeric project number automatically based on this logic please.

Thanks

Venkat