In the recent discussion here on Plouffe's new formula for calculating the decimal digits of pi [0] it was noted that fast calculation of Bernoulli numbers often requires knowing pi with decent precision. In Plouffe's paper he notes that it can be calculated using a multi-modular algorithm, but that would be too complex for a toy project like this so I stuck with a double sum.
[0] https://news.ycombinator.com/item?id=34389145