SageMath specific

• Planet SageMath Blogs — compilation of blogs by SageMath developers
• SageMath Cell Server — type some code to evaluate it immediately or embed it into your own website
• SageMath Wiki — helps to organize the development, formulate ideas and collect information
• SageMath in the news — collection of articles about SageMath
• CoCalc (formerly SageMathCloud) — run SageMath and much more online in your browser.
• Happy Ada Lovelace Day — women who have contributed to the SageMath (2010-03 blog post by Minh Van Nguyen) community

Links

• Sphinx — SageMath uses Sphinx to generate beautiful Python code documentation.
• Wikipedia: SageMath
• Python — primary programming language, both the interface and underlying infrastructure
• Cython — used by SageMath to interface with C/C++ libraries and to write easy maintainable compiled C code extensions for computation intensive parts
• Git — version control system used by SageMath

Related Projects & Software

• The Axiom Wiki, FriCAS, and OpenAxiom
• Macaulay 2 — High-quality algebraic geometry software under active development
• Java3d
• OpenOpt — Integrates solvers for numerical optimization into a single common Python-based framework.
• KASH/KANT — A free closed-source computer algebra system (superseded by Magma).
• Magma — Commercial closed-source software aimed at pure research mathematics and cryptography; the fastest software in the world at many computations.
• HECKE — William Stein wrote this program in C++ in 1999 for computing with modular forms.
• NTW — The number theory web site has a list of number theory software.
• NZMATH — Number theory software written in pure Python.