Sample size and mixed models

A very quick (and possibly silly) question for mixed modelers.  Certain 
metrics such as Nagelkerke's R2 and the sample size adjusted AICc 
require the user to specify the sample size.  What is the appropriate 
sample size to use in a mixed model where you might have hundreds of 
repeat samples on a smaller sample of sites (in this case, the sites are 
treated as the random factor)?  In my case, the lmer output will produce 
the following information: Number of obs: 10091, groups: ID, 444.  For 
calculating sample size adjusted statistics, would you use an effective 
sample size of 444?  Thank you.