rep() with each equals a vector
rep(1:5, vect1)
If you have questions about how to work functions in R, try
?function
where "function" is whatever function you want to know about. From ?rep you would have read:
'times' A integer vector giving the (non-negative) number of times to repeat each element if of length length(x), or to repeat the whole vector if of length 1. Negative or NA values are an error.