A069858 1/n has period 4 in base 10.

101, 202, 303, 404, 505, 606, 808, 909, 1010, 1111, 1212, 1515, 1616, 1818, 2020, 2222, 2424, 2525, 3030, 3232, 3333, 3636, 4040, 4444, 4545, 4848, 5050, 5555, 6060, 6464, 6666, 7272, 7575, 8080, 8888, 9090, 9696, 9999, 10100, 11110, 12120, 12625

Offset: 1

Author

Henry Bottomley, May 02 2002

Keywords

• base
• nonn

Examples

			1212 is in the sequence since 1/1212=0.0008250825082508250825082508250....
		

Crossrefs

Cf. A027894, A003592, A069105, A070021, A070022, A070023.

Programs

Mathematica

Select[Range[13000],Length[RealDigits[1/#][[1,-1]]]==4&] (* Harvey P. Dale, Jun 30 2017 *)

Formula

Numbers of the form a*b*c where a is in {101, 303, 909, 1111, 3333, 9999}, b is a power of 2 and c is a power of 5.