# A Dictionary of Real Numbers online?

Posted 10 years ago
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 I have a book, A Dictionary of Real Numbers, by Borwein and Borwein. If you're not familiar with it, it's a list of numbers that are the result of a limited number of operations on a limited number of numbers. The numbers printed are eight digits after the decimal point, truncated, not rounded. For example, if I come up with -2.403441 as the result of some calculations, I look in the book and find 40344144, and the book shows it came from 3Sqrt[2]/4-2Sqrt[3]. Of course this isn't a mathematical proof that the number I calculated is equal to 3Sqrt[2]/4-2Sqrt[3], but it does suggest a direction I might want to go if I do try to prove it.Is there anything like this online?
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Posted 10 years ago
 Thank you all. I put together all the pages (some related to others).For trying to find some symbolic form for a number you encounter or calculate:http://www.wolframalpha.com/http://mrob.com/pub/ries/index.htmlhttp://oldweb.cecm.sfu.ca/projects/ISC/http://oldweb.cecm.sfu.ca/projects/ISC/ISCmain.htmlhttp://isc.carma.newcastle.edu.au/For trying to identify integer sequences:http://oeis.org/
Posted 10 years ago
 In Mathematica you can just RootApproximant[0.403441, 2]And in Wolfram|Alpha type: 0.403441 closed form
Posted 10 years ago
 I wrote an answer, but then my internet connection got interrupted and I lost it.  Instead of rewriting it, I'm just going to post the relevant links:This is for Mathematica:http://mathematica.stackexchange.com/questions/16/can-mathematica-propose-an-exact-value-based-on-an-approximate-one/12These do what you asked:http://oldweb.cecm.sfu.ca/projects/ISC/http://isc.carma.newcastle.edu.au/This is for integer sequences, but you'll find answers to similar questions here as well:http://oeis.org/
Posted 10 years ago
 Thank you. This is useful, as is the answer I got when I posted under another discussion title, http://oldweb.cecm.sfu.ca/projects/ISC/ISCmain.html
Posted 10 years ago
 Wolfram Alpha can (sometimes) guess possible closed forms. There are also other specialized sites, here is one that identifies the example correctlyhttp://mrob.com/pub/ries/ries.php?target=-2.4034414433579333.