This dataset consists of about 270,000 MNIST-like captcha images. Each 84x30px image consists of 5 alphanumeric characters. I found the dataset useful for testing the UberAI Labs CoordConv method[1]. For interesting results you should use just a fraction of the 270k images for training. Also remember to split the dataset into a train and test set.
The filenames are structured like this:
captcha content
__font
.png
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