Repeating characters in VIM insert mode
If you are OK with leaving INSERT mode only once (at the end), this sequence works:
Ctrl+o 80i- Esc
- Ctrl+o is used to issue normal commands without leaving INSERT mode,
-
80the repetition, -
ito insert, -
-the character you want to insert, - Esc to leave INSERT mode.
Another one without EVER leaving INSERT mode:
Ctrl+o :norm 8ia Return
Escnic Esc Esc.
E.g. Esc4iJEsc Esc will output JJJJ.