[R] recursively divide a value to get a sequence

[Anne-Marie Ternes]

Hi,

if given the value of, say, 15000, I would like to be able to divide
that value recursively by, say, 5, and to get a vector of a determined
length, say 9, the last value being (set to) zero- i.e. like this:

15000 3000 600 120 24 4.8 0.96 0.192 0

These are in fact concentration values from an experiment. For my
script, I get only the starting value (here 15000), and the factor by
which concentration is divided for each well, the last one having, by
definition, no antagonist at all.

I have tried to use "seq", but it can "only" do positive or negative
increment. I didn't either find a way with "rep", "sweep" etc. These
function normally start from an existing vector, which is not the case
here, I have only got a single value to start with.

I suppose I could do something "loopy", but I'm sure there is a better
way to do it.

Thanks a lot for your help, hope the question is not too dumb...

Anne-Marie