Soulver - Soulver is a software application that functions as a calculator that allows you type a continuous stream of information rather than having to input data into multiple cells.
Observable - Interactive code examples/posts
Calca - Calca is an advanced symbolic calculator for iOS, OS X, and Windows that's as easy to use as a text editor.
nbviewer.org - Rackspace server host Jupyter Notebooks from your github repo
Numi App - Numi is a beautiful text calculator for Mac.
Jupyter - Project Jupyter exists to develop open-source software, open-standards, and services for interactive computing across dozens of programming languages. Ready to get started? Try it in your browser Install the Notebook.