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:

- whitespace
- decimal point(s)
- plus or minus signs
- leading (but not trailing) zeros

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