incrementing for loop by 2

Dear List-serv members: How can I structure a for loop so that it
will increment the counter by two using R?  I am just looking for a
simple example that shows where the incrementing part should go.
Thanks!

It would be helpful to have an idea of what you are trying to 
accomplish, as there may very well be a better way than using a 'for' loop.

That being said:

 > for (i in seq(0, 10, 2)) print(i)
[1] 0
[1] 2
[1] 4
[1] 6
[1] 8
[1] 10


See ?seq

HTH,

Marc Schwartz