Maybe it could be more efficient to go the other way round - instead of searching in the digits of pi kind of invert the BBP formula [1] and try to calculate th

Maybe it could be more efficient to go the other way round - instead of searching in the digits of pi kind of invert the BBP formula [1] and try to calculate the position of what you are looking for. But because the BBP formula involves rounding this is certainly not a simple task and I have really no idea if anything could be gained. [1] http://en.wikipedia.org/wiki/Bailey%E2%80%93Borwein%E2%80%93Plouffe_formula http://en.wikipedia.org/wiki/Bailey%E2%80%93Borwein%E2%80%93...