I have a library that finds out the the values of Pi up to a given number.

It takes 10x the time to calculate 3n than it takes to calculate n.

For example,

- For 1000 digits it takes 0.012 seconds
- For 3000 digits it takes 0.116 seconds
- For 9000 digits it takes 1.161 seconds
- For 27000 digits it takes 11.614 seconds
- For 81000 digits it takes 116.14 seconds
- For 243000 digits it takes 1161.4 seconds
- For 729000 digits it takes 11614.002 seconds
- For 2187000 digits it takes 116140.02 seconds
- For 6561000 digits it takes 1161400.2 seconds
- For 19683000 digits it takes 11614002.0 seconds

I have personally tried numbers up to 243,000, which really agrees with the calculation as well.

So, what will be the Big-O notation of this algorithm?