pythonize this!

[Stefan Behnel]

superpollo, 15.06.2010 14:55:
> Peter Otten ha scritto:
>> superpollo wrote:
>>
>>> goal (from e.c.m.): evaluate
>>> 1^2+2^2+3^2-4^2-5^2+6^2+7^2+8^2-9^2-10^2+...-2010^2, where each three
>>> consecutive + must be followed by two - (^ meaning ** in this context)
>>
>>>>> from itertools import cycle, izip
>>>>> sum(sign*i*i for sign, i in izip(cycle([1]*3+[-1]*2), range(1, 2011)))
>> 536926141
>
> don't understand it bit i like this a lot!

Didn't you want to get it "pythonized"? If it's not understandable, it 
can't be pythonic.

Stefan