This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A333607 #6 Mar 29 2020 17:15:32 %S A333607 1,2,3,5,9,10,11,15,18,20,25,30,33,45,50,90,99,100,101,110,111,125, %T A333607 150,165,180,198,200,225,250,300,303,330,333,450,495,500,900,909,990, %U A333607 999,1000,1001,1010,1100,1110,1111,1125,1250,1287,1500,1515,1650,1665,1800 %N A333607 Numbers k with unique nonzero digit in decimal representation of 1/k. %C A333607 This sequence has similarities with A125289; here we consider the decimal representation of 1/n, there that of n. %C A333607 This sequence contains A333402. %C A333607 If m belongs to the sequence, then 10*m also belongs to the sequence. %H A333607 Rémy Sigrist, <a href="/A333607/a333607.gp.txt">PARI program for A333607</a> %e A333607 The first terms, alongside their inverse, are: %e A333607 n a(n) 1/a(n) %e A333607 -- ---- ----------- %e A333607 1 1 1 %e A333607 2 2 0.5 %e A333607 3 3 0.333333... %e A333607 4 5 0.2 %e A333607 5 9 0.111111... %e A333607 6 10 0.1 %e A333607 7 11 0.090909... %e A333607 8 15 0.066666... %e A333607 9 18 0.055555... %e A333607 10 20 0.05 %e A333607 11 25 0.04 %e A333607 12 30 0.033333... %e A333607 13 33 0.030303... %o A333607 (PARI) See Links section. %Y A333607 Cf. A125289, A333402. %K A333607 nonn,base %O A333607 1,2 %A A333607 _Rémy Sigrist_, Mar 28 2020