```
C(0) = 1
C(1) = 1
C(n+1) = Sigma(r, 0, n, C(r) x C(n-r))
```

Where Sigma() means: Sigma(index var, lower bound, upper bound (inclusive), function(r)) I'm not familiar with standard Latex notation as I'm not a mathematician, so please ignore the sloppy presentation of the problem.