remove multiple elements from vector

Hello all,

one brief question

I would like to remove double/triple elements from a vector, e.g.

0 1 1 1 1 2 2 2 4 5 6 6

but keep one of these multiple ones. Should look like this finally:

0 1 2 4 5 6

My function does not work somehow

for(i in 2 : length(x)) {
                                 if(x[i]==x[i-1]) x <- x[-(i-1)]
                             }

any suggestion? Thanks.