you should look into while loops as well you can put the chan modes on one line

on @*:text:*:#: {
  if ($nick isop #) {
    if ($1 == !lockdown) {
      set $+(%,lockdown,.,$chan) on
      mode # +ism
      var %a = $nick(#,0,r), %o = 1
      while (%o <= %a) {
        ban -ku30 # $nick(#,%o,r) 2 Channel LockDown
        inc %o 
      }
    }
    if ($1 == !lockdownoff) { if ($($+(%,lockdown,.,$chan),2)) { mode # -ism | unset $+(%,lockdown,.,$chan) } }
  }
}
on @*:input:#: {
  if ($1 == !lockdown) {
    set $+(%,lockdown,.,$chan) on
    mode # +ism
    var %a = $nick(#,0,r), %o = 1
    while (%o <= %a) {
      ban -ku30 # $nick(#,%o,r) 2 Channel LockDown
      inc %o 
    }
  }
  if ($1 == !lockdownoff) { if ($($+(%,lockdown,.,$chan),2)) { mode # -ism | unset $+(%,lockdown,.,$chan) } }
}