At 200% daily interest, you're effectively tripling the initial value every day. So day 1 is x3, day 2 is x9, etc. The interest factor is then 3^365 for a year, not including the day the loan was made.
The total owed would then be (20,000)*3^365 = $2.82e178
For comparison, the estimated number of atoms in the observable universe is only 1e80