Sweet, I just discovered that the old classic 1000-page mathematical reference

*has been updated and distributed for the new millennium (well, and century too) in a more modern way. It's all there free on its own NIST website (the National Institute of Standards and Technology were the ones who published A&S in the first place back in the 1960s). Here it is right here:***Abramowitz and Stegun**
It was released just two years ago, with both a book version and this online version, which as far as I can tell is a superset of the book. Here are the three coolest practical aspects of the website version:

- next to each equation there's a permalink so you can reference a link straight back to the original section of the equation reference
- and perhaps even better, also next to each equation there's a link to the TeX source for the equation, so you don't even have to rework it all up in TeX again yourself when using it.
- and even better than that! - ALSO in each section is a list of links to modern software references for finding software libraries & codes to compute the quantities discussed in each section. (typically in Fortran; note for each code the link puts you at a bibliography entry for a relevant journal paper, but at the right of that ref there's another link that'll get you to the code and other related documents)

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**NIST Digital Library of Mathematical Functions**

(Note the Riemann zeta function used in their cover plot - for these 3D plots you can even interactively go zip around in them via VRML and X3D)