∑_{0≤n≤k}n²
expands to
\sum_{0\le n\le k} n^2.
Some of these are suboptimal. But you can just change them, and make your own.
[0]: http://lpaste.net/362623
∑_{0≤n≤k}n²
expands to
\sum_{0\le n\le k} n^2.