Paul Rubin ha scritto: > superpollo <utente at esempio.net> writes: >> 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) > > print sum([-1,1,1,1,-1][i%5]*i**2 for i in xrange(1,2011)) beautiful. thx