Possible Clues:

• In ___, one digit represents three binary digits
• Base eight-related
• The base eight number system
• Relating to a base eight system
• Kind of system in which 64 is 100
• Of a number system with base eight
• Using half as many digits as hexadecimal
• System in which 2017 is 3741
• Pertaining to or based on the number eight
• Number system in which this would be 143-Across