[R] oma and sub-title

[Thomas Steiner]

I want to add an outer subtitle to my 2x3-plot, but it's distance to the
lowest plots is very high: 6 lines or more?!
If I choose oma=c(5,0,2,0), it lies out of the plotting region and
disapprears. Obviously I make something wrong here. Help appreciated,
Thomas

x=seq(from=1, to=3.5, length=100)
par(mfrow = c(2, 3), oma=c(6,0,2,0))
## oma=c(5,0,2,0) will not work?!
plot(x,x^2)
plot(x,sin(x))
plot(x,exp(x))
plot(x,1/x)
plot(x,log(x))
plot(x,sin(1/x))
title(main="My Test", outer=TRUE, sub="my subtitle")