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 A335401 #16 May 06 2022 13:13:51
%S A335401 1,1,1,3,2,2,3,4,37,1,1,1,1,8,2,2,6,74,7,1,1,1,1,5,4,5,49,4,7,1,1,1,1,
%T A335401 3,6,37,3,29,8,3,3,5,7,3,74,5,26,25,27,2,2,6,4,43,2,2,23,4,17,2,2,5,
%U A335401 21,5,2,2,3,15,19,3,3,31,14,3,4,132,3,4,27,4,41
%N A335401 a(n) is the smallest positive number such that the decimal digits of n*a(n) are all 0, 1, 2 or 3.
%C A335401 If a(n) = k, then a(10n) = k.
%C A335401 a(n) = 1 iff n is in A007090; hence, except for a(1) = a(2) = a(3) = 1, the terms 1 always appear in strings of 4 consecutive 1's.
%C A335401 Records occur for n: 1, 4, 8, 9, 18, 76, ...
%F A335401 a(n) = A334914(n)/n.
%e A335401 a(9)= 37 because 9*37=333 is the smallest multiple of 9 whose decimal digits are all 0, 1, 2 or 3.
%t A335401 a[n_] := Block[{k = 1}, While[Max@ IntegerDigits[k n] > 3, k++]; k]; Array[a, 81] (* _Giovanni Resta_, Jun 06 2020 *)
%o A335401 (PARI) a(n) = my(k=1); while(vecmax(digits(k*n))>3, k++); k; \\ _Michel Marcus_, Jun 08 2020
%Y A335401 Cf. A007090, A334914.
%Y A335401 Cf. A079339 (similar, with digits 0 and 1), A181061 (similar, with digits 0, 1 and 2).
%K A335401 nonn,base
%O A335401 1,4
%A A335401 _Bernard Schott_, Jun 06 2020
%E A335401 More terms from _Giovanni Resta_, Jun 06 2020