Hey guys, im looking for step by step helpprovingthis identity. Im sans a calc book right now and i cant figure it out...

Again, a step by step would be most useful, my calculus is a little rusty, and i'm having to do this stuff for a computer algorithms course. I dont just need this particular answer, i need to be able to reproduce it on other questions.

Thanks a ton!

$\displaystyle

\sum^{n}_{k=1} k(k!) = (n + 1)! - 1

$