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 A198375 #18 Jan 21 2021 11:01:39
%S A198375 1,12,113,1114,11115,111116,1111117,11111118,111111119,1111111125,0,
%T A198375 111111111126,0,11111111111127,111111111111135,1111111111111128,0,
%U A198375 111111111111111129,0,11111111111111111145,111111111111111111137,0,0,111111111111111111111138
%N A198375 Smallest n-digit number whose product of digits is n or 0 if no number exists.
%H A198375 Michael S. Branicky, <a href="/A198375/b198375.txt">Table of n, a(n) for n = 1..1000</a>
%F A198375 a(A068191(n)) = 0 for n >=1.
%F A198375 a(n) <> 0 iff n in { A002473 }. - _Michael S. Branicky_, Jan 21 2021
%e A198375 113, 131, and 311 are the 3-digit numbers whose product of digits is 3; 113 is the smallest.
%t A198375 Table[If[FactorInteger[n][[-1, 1]] > 9, 0, i = (10^n - 1)/9; While[i < 10^n && Times @@ IntegerDigits[i] != n, i++]; If[i == 10^n, 0, i]], {n, 30}] (* _T. D. Noe_, Oct 24 2011 *)
%o A198375 (Python)
%o A198375 def A198375(n): return int(str(A198376(n))[::-1])
%o A198375 print([A198375(n) for n in range(1, 25)]) # _Michael S. Branicky_, Jan 21 2021
%Y A198375 Cf. A198376 (largest), A002473, A068191.
%K A198375 nonn,base
%O A198375 1,2
%A A198375 _Jaroslav Krizek_, Oct 23 2011