Let 

 be a probability assignment on the set of nonnegative integers where 

 is an arbitrary real number, 

 . We show that an optimal binary source code for this probability assignment is constructed as follows. Let 

 be the integer satisfying 

 and represent each nonnegative integer 

 as 

 when 

 , the integer part of 

 , and 
![r = [i] mod l](/images/tex/5638.gif)
 . Encode 

 by a unary code (i.e., 

 zeros followed by a single one), and encode 

 by a Huffman code, using codewords of length 

 , for 

 , and length 

 otherwise. An optimal code for the nonnegative integers is the concatenation of those two codes.