#### 2.4.8.10 Sharpsign X ¶

`#X` rational reads rational in hexadecimal (radix 16). The digits above `9` are the letters `A` through `F` (the lowercase letters `a` through `f` are also acceptable). For example,

     #xF00 ≡ 3840
     #x105 ≡ 261 ;105_16

The consequences are undefined if the token immediately following the `#X` does not have the syntax of a hexadecimal (i.e., radix 16) rational.