When numbers repeat, the value is the same. E.g 00 is the same as 00.
So the possible outcomes is 6^16, but unique values per color channel is only 256 values.
So unique colors are 256^3 = 16.7M colors.
/000000 /000001 /000002 /000003 etc...
Or am I missing something?
So how many 6-digit hexadecimal numbers from 0x000000 to 0xffffff? 0xffffff+1 = 16777216 = 16^6. 16 options for the first digit, times 16 options for the second digit, times 16 for the 3rd, times 16 for the 4th, times 16 for the 5th, times 16 for the 6th is 16^6. Or go to bytes: 3 bytes, each with 256 possible values is 256^3 = (16^2)^3 = 16^6. Or bits: 2^24 = (2^4)^6 = 16^6.
It's also pretty trivial to just count them. Run this in your browser console:
count = 0; for(i = 0x000000; i <= 0xffffff; i++) { count++; } console.log(count, 16**6, 0xffffff+1, 6**16)16^6 is not 6^16.
3 bytes (24 bits) is 2^24 (16777216 unique combinations of bits)
The first has 16 possible values;
The second also has 16 possible values for each of those 16, so now we have 16 times 16.
etc.
So it's a choice from 16, repeated for a total of 6 times.
That's 16 times 16 times ... times 16, which is 16^6.