Google Code-in 2011 Organization SymPy Task S('x!') fails (should be factorial(x))

completed by: Grzegorz Świrski

mentors: Aaron Meurer

Please see http://code.google.com/p/sympy/issues/detail?id=2889 for full information on this task.

Please read https://github.com/sympy/sympy/wiki/gci-2011-landing before completing any tasks for SymPy.