[SOLVED] Regex - Match repeated character not in sequence

Is there a way to match repeated characters that are not in a sequence?

Let's say I'm looking for at least two 6s in the string.

var string = "61236";

I can only find quantifiers that match either zero or one or characters in a sequence.

Here is a regexp that matches a character that is followed somehwere in the string by the same digit:

/(.)(?=.*?\1)/

Usage:

var test = '0612364';
test.match(/(.)(?=.*?\1)/)[0] // 6

Here is one that matches it repeated at least 3 times (total of 4+ occurances)

/(.)(?=(.*?\1){3,})/