$$
\begin{align*}
f_t &= \sigma(W_f [h_{t-1}, x_t] + b_f), \\
i_t &= \sigma(W_i [h_{t-1}, x_t] + b_i), \\
\tilde{C}_t &= \tanh(W_C [h_{t-1}, x_t] + b_C), \\
C_t &= f_t \odot C_{t-1} + i_t \odot \tilde{C}_t, \\
o_t &= \sigma(W_o [h_{t-1}, x_t] + b_o), \\
h_t &= o_t \odot \tanh(C_t).
\end{align*}
$$