Regular Number

Author

Eric W. Weisstein
April 2, 2006

This notebook downloaded from http://mathworld.wolfram.com/notebooks/Arithmetic/RegularNumber.nb.

For more information, see Eric's MathWorld entry http://mathworld.wolfram.com/RegularNumber.html.

©2006 Wolfram Research, Inc. except for portions noted otherwise

Enumeration

regular=Select[1/Range[50],DecimalPeriod[#]==0&]

DecimalExpansion/@regular//TraditionalForm

1/regular

Decimal Lengths

DecimalLength[n_]:=Module[{i=IntegerExponent[n,#]&/@{2,5}},
If[n==Times@@Power@@@Transpose[{{2,5},i}],Max[i],0]
]

DecimalLength/@Range[200]

DeleteCases[%,0]

HighWaterMarks[DecimalLength/@Range[1024]]