A333607 Numbers k with unique nonzero digit in decimal representation of 1/k.

1, 2, 3, 5, 9, 10, 11, 15, 18, 20, 25, 30, 33, 45, 50, 90, 99, 100, 101, 110, 111, 125, 150, 165, 180, 198, 200, 225, 250, 300, 303, 330, 333, 450, 495, 500, 900, 909, 990, 999, 1000, 1001, 1010, 1100, 1110, 1111, 1125, 1250, 1287, 1500, 1515, 1650, 1665, 1800

Offset

1,2

Comments

This sequence has similarities with A125289; here we consider the decimal representation of 1/n, there that of n.

This sequence contains A333402.

If m belongs to the sequence, then 10*m also belongs to the sequence.

Links

Table of n, a(n) for n=1..54.

Rémy Sigrist, PARI program for A333607

Example

The first terms, alongside their inverse, are:
  n   a(n)  1/a(n)
  --  ----  -----------
   1     1  1
   2     2  0.5
   3     3  0.333333...
   4     5  0.2
   5     9  0.111111...
   6    10  0.1
   7    11  0.090909...
   8    15  0.066666...
   9    18  0.055555...
  10    20  0.05
  11    25  0.04
  12    30  0.033333...
  13    33  0.030303...

Prog

(PARI) See Links section.

Crossrefs

Cf. A125289, A333402.

Sequence in context: A127149 A047606 A226826 * A047370 A226820 A072192

Adjacent sequences: A333604 A333605 A333606 * A333608 A333609 A333610

Keyword

nonn,base

Author

Rémy Sigrist, Mar 28 2020

Status

approved