This worked, thank you! One more problem though: The results are not pretty-printed using MathJax automatically, and if I surround the command with "pretty_print(...)", it prints the HTML code rather than rendering it. How can I activate MathJax rendering by default?

I agree with @ppurka explanation (i was going to answer along the same lines before his/her solution appears ;) and the workaround to have the preparser work in a ipython shell (or notebook) is to type:

%load_ext sage.misc.sage_extension

as suggested here

If I start the command line version of sage with sage and type

integrate(x^2,x)

I get

1/3*x^3

as desired.

However, if I start sage in IPython's notebook with sage -ipython notebook and type the same thing I get

NameError: name 'integrate' is not defined

Trying to fix this by defining some prerequisites

from sage.all import *
,var x

I now get

RuntimeError: Use ** for exponentiation, not '^', which means xor
in Python, and has the wrong precedence.

In other words, it is clear that sage -ipython notebook does not provide the same environment as sage.

How can I fix this? I just want an IPython notebook that works like my sage command line.