It is true that in Keras the RNN layer is waiting for input as (nb_samples, time_steps, input_dim). However, if you want to add an RNN layer after the Dense layer, you can still do this after changing the input for the RNN layer. Reshape can be used both as a first layer and as an intermediate level in a sequential model. Examples are given below:
Solve as the first level in a sequential model
model = Sequential()
model.add(Reshape((3, 4), input_shape=(12,)))
model.add(Reshape((6, 2)))
# now: model.output_shape == (None, 6, 2)
, , . , - . .
from keras.models import Sequential
from keras.layers import Dense, SimpleRNN, Reshape
from keras.optimizers import Adam
model = Sequential()
model.add(Dense(150, input_dim=23,init='normal',activation='relu'))
model.add(Dense(80,activation='relu',init='normal'))
model.add(Reshape((1, 80)))
model.add(SimpleRNN(2,init='normal'))
adam = Adam(lr=0.001, beta_1=0.9, beta_2=0.999, epsilon=1e-08)
model.compile(loss="mean_squared_error", optimizer="rmsprop")