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Katadrome


A katadrome is a number whose hexadecimal digits are in strict descending order. The first few are 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 32, 33, 48, 49, ... (OEIS A023797), corresponding to 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F, 10, 20, 21, 30, 31, ....

A number that is not a katadrome is a plaindrome.

The following table summarized related classes of numbers.

namebase-16 digit order
katadromestrict descending
metadromestrict ascending
nialpdromenonincreasing
plaindromenondecreasing

See also

Digit, Hexadecimal, Metadrome, Nialpdrome, Plaindrome

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References

Sloane, N. J. A. Sequence A023797 in "The On-Line Encyclopedia of Integer Sequences."

Referenced on Wolfram|Alpha

Katadrome

Cite this as:

Weisstein, Eric W. "Katadrome." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Katadrome.html

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