PAN digits Significance

Dear freind,

Fourth & Fifth alphabets in PAN are important for they are not any random or sequentially alloted alphabets, rather they represent nature of assessee/ person and its name.

Fourth alphabet signifies type/ category of person, the allotee is:-

P - Individual

H - HUF

C - Company

T - Trust, etc.

While the fifth alphabet is the first letter of individual's last name or  name, in case of any other person.

What is the significance of rest of all the digits and numbers?