I suggest using regex to match subdirectories of version number exactly:
find . -type d -iregex '^\./course\([0-9]\.\)*[0-9]$'
TESTS:
ls -d course*
course1.1.0.0 course1.1.0.5 course1.2.0.0 course1.txt
find . -type d -iregex '^\./course\([0-9]\.\)*[0-9]$'
./course1.1.0.0
./course1.1.0.5
./course1.2.0.0
UPDATE: To match [0-9].exactly 3 times, use this find command:
find test -type d -regex '.*/course[0-9]\.[0-9]\.[0-9]\.[0-9]$'
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