4 Folded. This doesn't make sense without alternatives, but it works.
9 \context Staff \notes \relative c'' {
10 \repeat fold 3 { c^"3$\\times$ 0alt" d }
12 \repeat fold 4 { c^"4$\\times$ 2alt" d } \alternative { e f }
14 \repeat fold 2 { c^"2$\\times$ 3alt" d } \alternative { e f g }