A070023 1/n has period 1 in base 10 (including terminating decimals).

1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 25, 30, 32, 36, 40, 45, 48, 50, 60, 64, 72, 75, 80, 90, 96, 100, 120, 125, 128, 144, 150, 160, 180, 192, 200, 225, 240, 250, 256, 288, 300, 320, 360, 375, 384, 400, 450, 480, 500, 512, 576, 600, 625, 640, 720, 750

Offset

1,2

Links

Table of n, a(n) for n=1..61.

Formula

a(n) = A070022(n)/11. Numbers of the form a*b*c where a is in {1, 3, 9}, b is a power of 2 and c is a power of 5.

Example

12 is in the sequence since 1/12 = 0.08333333333...
11 is not since 1/11 = 0.0909090909...
10 is in, since 1/10 = 0.1000000... = 0.099999999...

Mathematica

Select[Range[750], Length[RealDigits[1/#][[1, -1]]] <= 1 &] (* Amiram Eldar, Jun 12 2022 *)

Crossrefs

Cf. A003592, A069105, A070021, A070022.

Sequence in context: A051037 A250089 A257997 * A035303 A291719 A360425

Adjacent sequences: A070020 A070021 A070022 * A070024 A070025 A070026

Keyword

base,nonn

Author

Henry Bottomley, Apr 12 2002

Status

approved