[R] display math with subscripts from a sequence

[Ranjan Maitra]

Dear friends,

I am trying to display a sequence of characters x_1, x_2, ... x_30 on a plot.

I know that I can use expression to  do this by expression("x"[1]), etc. But, how do I do this efficiently for an entire sequence without having to type the individual expressions one by one?

Many thanks,
Ranjan