https://oeis.org/ - On-Line Encyclopedia of Integer Sequences
http://mathworld.wolfram.com/ - Wolfram Math World
http://www.lmfdb.org/ - LMFDB - The L-functions and modular forms database

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https://github.com/webMath - webMath
https://bl.ocks.org/ - Popular Blocks - bl.ocks.org
https://threejs.org/ - three.js - Javascript 3D library
http://analyticphysics.com/ - Analytic Physics

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https://www.sagemath.org/ - SageMath - Open-Source Mathematical Software System
https://jupyter.org/ - Project Jupyter | Home
https://www.gap-system.org/ - GAP System for Computational Discrete Algebra
https://www.sympy.org/ - SymPy
http://maxima.sourceforge.net/ - Maxima, a Computer Algebra System
https://www.r-project.org/ - R: The R Project for Statistical Computing
https://pandas.pydata.org/ - Python Data Analysis Library — pandas: Python Data Analysis Library
http://www.statsmodels.org/ - StatsModels: Statistics in Python — statsmodels 0.9.0 documentation
http://scikit-learn.org/ - scikit-learn: machine learning in Python — scikit-learn 0.19.1 documentation
https://www.tensorflow.org/ - TensorFlow
http://www.nltk.org/ - Natural Language Toolkit — NLTK 3.3 documentation
https://www.gnu.org/software/octave/ - GNU Octave
https://julialang.org/ - The Julia Language
https://www.latex-project.org/ - LaTeX - A document preparation system

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https://gmplib.org/ - The GNU Multiple Precision Arithmetic Library