## SymbolicSum3

`SymbolicSum3` is similar to `SymbolicSum` (`SymbolicSum` was a Mathematica function to do symbolic summation. It was obsolete from version 3 - all functionality is now autoloaded by `Sum`), but extended to several double sums.

### See also

[Overview](Extra/FeynCalc.md), [SymbolicSum2](SymbolicSum2.md).

### Examples