rep(x, times, length.out)
rep replicates the values in x
according to the values given in times
and length.out.
If times consists of a single integer,
the result consists of the values in
x repeated this many times.
If times is a vector of the same length as
x, the result consists of x[1]
repeated times[1] times,
x[2] repeated times[2] times and so on.
length.out may be given in place of times,
in which case x
is repeated as many times as is necessary
to create a vector of this length.
seq, sequence.rep(1:4,2) rep(1:4,c(2,2,2,2))