Give a closed expression for the infinite sum:

1/1 + 2/(2+3) + 3/(4+5+6) + 4/(7+8+9+10) + ...

(In reply to

No Subject by Vee-Liem Veefessional)

A closed expression is just a formula -- if you want to calculate the sum, instead of summing infinite terms you just evaluate the formula.

The sum is called infinite because it has infinitely many terms.

Yes, it can be solved!