FUNCTION :  ETA[POWERPqMODP] -  q-expansion of power of q-series mod p

PARAMETERS :
    a - q-series    
    N,M,p - positive integers

GLOBAL VARIABLES : 

SYNOPSIS :   
   Compute a^N to O(q^M) mod p (where N>=0)

EXAMPLES :   

DISCUSSION :

SEE ALSO :