Undenary, also called undecimal, is the base-11 numeral system. Its eleven digits can be written 0, 1, 2, 3,
4, 5, 6, 7, 8, 9, and A, with A representing the value 10. In expanded
notation, an undenary numeral 
represents the nonnegative
integer
where each 
is a digit value from 0 to 10. For example, 
in decimal.
The place values of the fractional part are the
negative powers 
, 
,
....
The undenary digit sums of successive nonnegative integers, beginning with 0, are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, ... (OEIS
A053831).
See also
Base,
Decimal,
Digit,
Expanded Notation,
Numeral System
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References
De Vlieger, M. T. "Multiplication Tables of Various Bases." Updated Nov. 24, 2014. https://dozenal.org/drupal/sites_bck/default/files/MultiplicationSynopsis.pdf.Math
Is Fun. "Number Bases." https://www.mathsisfun.com/numbers/bases.html.Sloane,
N. J. A. Sequence A053831 in "The
On-Line Encyclopedia of Integer Sequences."
Cite this as:
Weisstein, Eric W. "Undenary." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Undenary.html
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