R code that gives results like Wolfram Alpha for the expectation of a function of a random variable? [closed]

When I ask Wolfram Alpha to calculate $$E[f(X)]$$ where $$f(x) = e^{-x^2}$$ and $$X \sim \mathcal{N}(1,4)$$, it gives the result $$E[f(X)] = \frac{1}{3\sqrt[9]{e}} \approx 0.29828,$$ and the following plot which appears to be based on taking a number of simulations:

How can I generate the same type of plot using R?

library(ggplot2)