rnn is an open-source machine learning framework that implements recurrent neural network architectures, such as LSTM and GRU, natively in the R programming language, that has been downloaded over 100,000 times (from the RStudio servers alone).

[1] The rnn package is distributed through the Comprehensive R Archive Network[2] under the open-source GPL v3 license.

The below example from the rnn documentation show how to train a recurrent neural network to solve the problem of bit-by-bit binary addition.

[3] With the release of version 0.3.0 in April 2016[4] the use in production and research environments became more widespread.

The package was reviewed several months later on the R blog The Beginner Programmer as "R provides a simple and very user friendly package named rnn for working with recurrent neural networks.