NumberDBbeta

The searchbar can be used to search for:
• Real numbers:
Enter the number in one of three formats:
• 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).
• Scientific notation (no period necessary), e.g. "14e2" to search numbers between 1300 and 1500.
• 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.
• Fractional parts of real numbers:
Enter the first few digits after the period, e.g. "1415" for pi.
• Integers:
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.
• Complex numbers:
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.
• $p$-adic numbers:
Search for numbers in $\mathbb{Q}_p$ in one of two formats:
• 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 $-(2 + 2\cdot 3^1) + O(3^3)$.
• 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)".
• Tables:
Enter words from the table's title, keywords, tags, definition, or comments.
• Tags:
Enter the first letters of one word of a tag, e.g. "irr" for the tag "Irrational".