I was surprised the answer was 2 myself since it's the same as the 2^-n series, but I looked it up.
However they switch term-wise with the triangular numbers reciprocals first smaller then larger than the geometric.
I know that re-grouping terms doesn't always work as (1+-1)+(1+-1)+...≠1+(-1+1)+(-1+1)... but since I got the correct answer I want to know if I was somehow "cheating."
re(2): Is this valid? no ! - partial spoiler
