A scientific, encyclopedic, collaborative database of numbers.
The searchbar can be used to search for:
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Enter the number in one of three formats:
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Decimal representation including the period,
e.g. "3.14" to search for pi.
The search will be done in an interval around the entered number:
Entering "3.14" will search for numbers in the interval (3.13, 3.15).
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Scientific notation (no period necessary),
e.g. "14e2" to search numbers between 1300 and 1500.
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NumberDB's p-notation:
Enter a term of the form "ApB", where A and B are integers.
It corresponds to the number 10A · 0.B, e.g. "1p314" for pi.
The sign of the number is determined by the sign of B.
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Enter the first few digits after the period, e.g. "1415" for pi.
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Enter the exact integer without period, e.g. "-1".
This works for integers with up to 127 binary digits (roughly 38 decimal digits).
For longer integers,
try to search them as real numbers.
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Enter sums or differences of the form "A" or "i*A" or "A*i", where "A" is a
real number in the above format
or a rational number.
Entering "-1/2 + i * 0.86602" (to search for a third root of unity) will
search within a larger square around it.
Both, real and imaginary parts need sufficient precision.
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Search for numbers in $\mathbb{Q}_p$ in one of two formats:
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Enter "Q2:1010" to search for $2^0 + 2^2 + O(2^5)$.
Enter "Q2:1.1010" to search for $2^{-1} + 2^0 + 2^2 + O(2^5)$.
For $p>10$, any $p$-adic digit needs to be given in base 10 with the same number of base 10 letters as $p$,
e.g. "Q13:0102" will search for $13$-adic numbers of the form $1+2\cdot 13 + O(13^2)$.
Minus signs are also interpreted, e.g. "Q3:-220" searches for $-(2 + 2\cdot 3^1) + O(3^3)$.
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Enter "3 + O(2^5)" or "2^0+2^1+O(2^5)" for numbers of the form $2^0 + 2^2 + O(2^5)$.
This format also works for $\mathbb{Q}_p$, e.g. enter "3/5 + O(5^1)".
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Enter polynomials over $\mathbb{Q}$ in arbitrary variables,
e.g. enter "x^6+y^6-x^5*y^5+4*x*y" to search for $x^6+y^6-x^5y^5+4xy$.
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Enter words from the table's title, keywords, tags, definition, or comments.
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Enter the first letters of one word of a tag, e.g. "irr" for the tag "Irrational".
