Oban number
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Oban numbers are defined as numbers who don't contain the letter 'o' when spelled in English. This definition is not definitive as some large numbers don't follow the guidelines for naming of numbers.
The first oban numbers are: 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 18, 19, 20, 23, 25, 26, ...
Due to the fact that every number name for a power of 10 greater than 3 contains the suffix thousand or -illion, the list of oban numbers is finite. There are exactly 454 and the largest one is 999.
[edit] See also
[edit] References
- Weisstein, Eric W., Oban Number at MathWorld.