Chord progressions of 25,000 songs
"So for example, the transition 4->1->5->6 is one of the most popular ones"
The graph does not show this or I'm misunderstanding something. The most popular looks like 1,4,1,5<p>Also, what does the double, triple numbers mean? 664, 66 in the fist column. I know some music theory, but the article's explanation is rather confusing.