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  Two factorials   and   are the particular cases of the incomplete gamma function   with the second argument being  : 
 
 
 
 The factorial  , double factorial  , Pochhammer symbol  , binomial coefficient  , and multinomial coefficient   can be represented through the gamma function by the following formulas: 
 
 
 
 
 
 
 
 
 Many of these formulas are used as the main elements of the definitions of many functions. 
 
 The factorials and binomials  ,  ,  ,  , and   are interconnected by the following formulas: 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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