R help - Jun 2017 - Estimating Unbiased Standard Deviation with Autocorrelation

Hello,
I have a vector of values with significant autocorrelation, and I want to
calculate an unbiased standard deviation that adjusts for the autocorrelation.
The formula linked below purports to provide what I want:

https://en.wikipedia.org/wiki/Unbiased_estimation_of_standard_deviation#Effect_of_autocorrelation_.28serial_correlation.29

However, rather than just implementing this equation in my own function, I
figured there is likely already an R function that does this, and perhaps does a
better job of handling the subtleties of the adjustment when the ACF itself is
estimated from the same data that is used to estimate the sample standard
deviation (if there are any).
 
If such a function exists, can anyone point me to it?

Thanks in advance,
Robert