[R] Efficient way to find consecutive integers in vector?

[Johannes Graumann]

Hi all,

Does anybody have a magic trick handy to isolate directly consecutive
integers from something like this:
c(1,2,3,4,7,8,9,10,12,13)

The result should be, that groups 1-4, 7-10 and 12-13 are consecutive
integers ...

Thanks for any hints, Joh