"Hello world!", repeating each character n times

Brainfuck

n=57. 45 newlines removed thanks to ratchet freak

++++++++++[>+++++++>++++++++++>+++<<<-]>++.>+.+++++++..+++.>++.<++++++++.--------.+++.------.--------.>+.---------------------------------[.............................................][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]<-<<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><

A more readable version:

+++++ +++++ [
    > +++++ ++
    > +++++ +++++
    > +++
    <<< -
]
> ++ .
> + .
+++++ ++.
.
+++ .
> ++ .
< +++++ +++ .
----- --- .
+++ .
----- - .
----- --- .
> + .
---------------------------------[.............................................][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]<-<<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><

The last line (on the readable version) is for filling up the character count. They are not comments. The [] are while(0)s, and the ><s are in essence no-ops

JavaScript

alert(("aaaeerrttt((,,,HHHoo   wwwddd!!!))","Hello world!"))

This seemed a little too easy.

Python 3, n = 3, no comments

dwwppHottedHen =print((("H[e]l1l1o\\ !w!orrilidn!\""[::2][:12])))== 2

Not too hard for a Pythonist to understand. ;) (Hint: try "abcdefghijk"[::2] and see what it results in)

By the way, a HottedHen is a warmed up chicken, if you were wondering. (The dwwpp before it stands for drinking water with purple pancakes, because that's what the hens were doing when I was writing it. Everyone knows that purple pancakes go well with water. Obviously.)