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Scroll down for "How to use it", "Credits" and "Glossary".

How to use it

Enter a string of 5 or more digits to search. Hover over red underlined terms for their explanation.
Some results will be turned into relevant hyperlinks (eg. to entries in the Online Encyclopedia of Integer Sequences).

The following will be ignored: Thus, results may need to be multiplied by some power of 10 and/or -1 to obtain the entered value.

Credits

This page is a shadow of the former Inverse Symbolic Calculator (ISC), and (only) uses the lookup tables from that project, "to associate a closed form representation with a user-[specified], truncated decimal expansion". The lookup tables include a substantial data set compiled by Simon Plouffe both before and during his period as an employee at CECM. The interested user is directed to his much more comprehensive and up to date tables at plouffe.fr/ipgz/ [update May 2020: the files are no longer available there, try the Internet Archive instead]. CRI was written by David Allingham using the ISC look-up tables.

Glossary

Artin: Artin constant, 0.37395 58136 19202 28805...
Backhouse: Backhouse's constant, 1.45607 49485 82689 67139...
Bernstein: Bernstein's constant, 0.28016 94990 23869 13303...
Cahen: Cahen's constant, 0.64341 05462 88338 02618...
Catalan: Catalan's constant, 0.91596 55941 77219 01505...
C des nbrs premiers jumeaux: Twin Primes constant, 0.66016 18158 46869 57392...
cos: The cosine function
Digits: 'Digits of S from rank N' means the digits AFTER the Nth place
E.I.S.: Online Encyclopedia of Integer Sequences, https://oeis.org/
exp: The exponential function
GAM: The gamma function, see http://mathworld.wolfram.com/GammaFunction.html
Gibbs: Gibbs constant, 1.85193 70519 82466 17036...
Golomb: Golomb-Dickman constant, 0.62432 99885 43550 87099...
Im: The imaginary part
inf: Infinity
Khint: Khinchin's constant, 2.68545 20010 65306 44530...
Khintchine: Khinchin's constant, 2.68545 20010 65306 44530...
ln: The natural logarithm
Madelung: Madelung constant, 5.97798 68121 78349 12266...
Parking: Rényi's Parking Constant, 0.74759 79202 53411 43517...
Pi: Pi, the ratio of a circle's circumference to its diameter
Psi: The digamma function, see http://mathworld.wolfram.com/PolygammaFunction.html
Re: The real part
sin: The sine function
sqrt: The square-root function
sr: The square-root function
ThueMorse: Prouhet-Thue-Morse constant, 0.41245 40336 40107 59778...
TwinPrim: Twin Primes constant, 0.66016 18158 46869 57392...
Twin primes constant: Twin Primes constant, 0.66016 18158 46869 57392...
W: The Lambert W-function, also called the product log function, see http://mathworld.wolfram.com/LambertW-Function.html
Zeta: With one argument, the Riemann Zeta function, see http://mathworld.wolfram.com/RiemannZetaFunction.html. With two arguments, the generalized (or Hurwitz) Zeta function, see http://mathworld.wolfram.com/HurwitzZetaFunction.html