(Binary numbers are shown in dark blue .)
0 1 = Zero = One
10 = Two
10011 = Three = Four
101110 = Five = Six
1000111 = Seven = Eight
10011010 = Nine = Ten
1011 = Eleven
11001101 = Twelve = Thirteen
11101111 = Fourteen = Fifteen
1000010001 = Sixteen = Seventeen
10010 = Eighteen
1001110100 = Nineteen = Twenty
.
..
Notice how binary numbers can be found by excluding numbers that have a 2, 3, 4, 5, 6, 7, 8, or
9.
(^0 1)
(^2 3)
4
(^5 6)
7
(^8 9)
10
1211
(^13 14)
(^15 16)
(^17 18)
19
(^20 21)
(^22).
..