For learning system administration, I think Cent OS Stream can be a great choice. Not because it offers something special than others but because it would familiarize you with the RHEL/Fedora family and in my experience majority of enterprise-servers are using one of its family members, be it RHEL, the former CentOS, Oracle Linux, Amazon Linux or some other variant.
TLDR: In octal system, the weight of the digit in a position is an exponent of 8. So 31 = (3×8¹ + 1×8⁰) = (3×8 + 1×1) = 24 + 1 = 25.