Base prefix notation

Using Arduino Programming Questions
4

0bnnnnnnnn is C/C++

Bnnnnnnnn is a set of #defines in hardware/arduino/cores/arduino/binary.h:

#define B0 0
#define B00 0
#define B000 0
#define B0000 0
#define B00000 0
#define B000000 0
#define B0000000 0
#define B00000000 0
#define B1 1
#define B01 1
#define B001 1
...

If you want to be "proper", use 0bnnnnnnnn.

And base 5 is common in counting. I, II, III, IIII, IIII