20 Day Low

Hope I understood correctly - try this:

// today's low is the lowest in 20 days

and [low = min(20, low)]

// within the 5 day period ending 5 days ago, the low is equal to
// the low within the 20 day period ending 5 days ago

and [5 days ago min(5, low) = 5 days ago min(20, low)]

// today's close is above the minimum low in the 5 day period ending 5 days ago

and [close > 5 days ago min(5, low)]

It appears to catch some potential double bottoms.

When you look at the results, see if the most successful examples have higher volume on today's close versus yesterday's, and better yet, higher volume above the 21 day average.
Early buying is often strong buying. On the other hand, a Wyckoff rule for testing a low is that you actually want a low below and a close above a past low on weak volume.