> with(qseries);
[aqprod, changes, etamake, etaq, findhom, findhomcombo, findhomcombomodp,

    findhommodp, findlincombo, findnonhom, findnonhomcombo, findpoly, jac2prod,

    jac2series, jacprod, jacprodmake, mprodmake, packageversion, prodmake, qbin,

    qetamake, qfactor, quinprod, sift, theta, theta2, theta3, theta4,

    tripleprod, winquist, zqfactor]

> 
> x:=add(q^(n*(n+1)/2),n=0..20);
              3    6    10    15    21    28    36    45    55    66    78
x := 1 + q + q  + q  + q   + q   + q   + q   + q   + q   + q   + q   + q

        91    105    120    136    153    171    190    210
     + q   + q    + q    + q    + q    + q    + q    + q

> 
> etamake(x,q,20);
                                            2
                                  eta(2 tau)
                                 -------------
                                  1/8
                                 q    eta(tau)

> 
> qetamake(x,q,20);
                                        2 2
                                    _E(q )
                                    -------
                                     _E(q)

>