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 A381530 #11 Mar 02 2025 23:21:18
%S A381530 1,2,2,3,3,4,4,5,5,1,1,1,1,1,1,1,1,1,1,2,1,2,2,2,2,2,2,2,2,2,1,2,2,2,
%T A381530 2,2,2,2,2,3,1,2,2,3,3,3,3,3,3,3,1,3,3,3,3,3,3,3,3,4,1,2,2,3,3,4,4,4,
%U A381530 4,4,1,4,4,4,4,4,4,4,4,5,1,2,2,4,4,4,4,5,5,5,1,5,3,3,3,5,5,5,5,1
%N A381530 a(n) is the least k > 0 such that n / k contains a digit 1 in its decimal representation.
%e A381530 n = 7:
%e A381530 7/1 = 7
%e A381530 7/2 = 3.5
%e A381530 7/3 = 2.33...
%e A381530 7/4 = 1.75 contains a digit 1, thus a(7) = 4.
%t A381530 a[n_] := Module[{k = 1}, While[FreeQ[RealDigits[n/k][[1]], 1], k++]; k]; Array[a, 100] (* _Amiram Eldar_, Feb 26 2025 *)
%Y A381530 Cf. A317173, A371706.
%K A381530 nonn,base
%O A381530 1,2
%A A381530 _Ctibor O. Zizka_, Feb 26 2025