FUNCTION :  qseries[theta4] - the theta function  theta (q)
                                                       4
CALLING SEQUENCE :  theta4(q,T)       
    
PARAMETERS :   q   - variable 
               T   - positive integer 
   
SYNOPSIS :   
                                                        T 
 theta4(q,t) returns the q-series expansion to order O(q ) of 

                                  oo
                                 -----          2
                                  \         n  n
              theta (q)   =        )    (-1)  q
                   4              /
                                 -----
                                n = - oo

EXAMPLES :   
   
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> theta4(q,50);                             

            64      49      36      25      16      9      4
         2 q   - 2 q   + 2 q   - 2 q   + 2 q   - 2 q  + 2 q  - 2 q + 1

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SEE  ALSO :   jacprod, tripleprod, theta, theta2, theta3