: They originally planned for 17 members, but 4 trainees left before debut.
The sub-unit consists of three members: Seungkwan , DK , and Hoshi . The number 301 is a common shorthand or "code" used by fans (Carats) to represent this specific trio: 3 members in the unit. Seventeen 301
: Their 5th Studio Album, HAPPY BURSTDAY (released May 2025), features 13 solo tracks—one for every member—showcasing their individual "proper" musical styles. : They originally planned for 17 members, but
: Their "FOLLOW AGAIN" tour featured Ultra 4DX and ScreenX cinema releases, providing a 270-degree viewing experience. 🏛️ The "17" Formula HAPPY BURSTDAY (released May 2025)