So What Does 1+2+3+4+... Equal? We Give You the Answer

Solving the mystery of the controversial (and errant) claim that 1+2+3+4+... =-1/12. (Scroll to the bottom if you want to skip the details and get right to the answer.)   Despite some interesting math the Numberphiles posted, and even a "proof" courtesy of Euler, the sum of the natural numbers (1,2,3,4, up to infinity) don't equal -1/12, as you can see graphically in my last post on the subject.So what does it equal? The obvious answer is that it goes to infinity, but it's an unsatisfying one ...