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 A270027 #24 Jun 29 2019 01:46:28
%S A270027 0,0,3,4,5,3,7,4,3,3,3,3,13,7,3,4,4,3,3,3,3,11,23,3,5,5,3,3,3,3,3,3,3,
%T A270027 3,3,3,3,3,3,4,6,3,43,4,3,3,3,3,4,4,3,4,5,3,3,3,3,3,3,3,3,3,3,3,3,3,4,
%U A270027 4,3,4,4,3,3,3,3,4,4,3,4,4,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3
%N A270027 a(n) is the smallest b >= 3 for which the base-b representation of n contains at least one 0 (or 0 if no such base exists).
%C A270027 It is natural to consider this sequence starting from base 3 instead of base 2, as the latter causes most terms to be 2 (see A270026).
%C A270027 a(n) = n if and only if n = 3 or n is in A069575.
%C A270027 a(n) > 0 for n >= 3 since the base-n representation of n is 10.
%H A270027 Nathan Fox, <a href="/A270027/b270027.txt">Table of n, a(n) for n = 1..10000</a>
%t A270027 Table[SelectFirst[Range[3, 10^3], DigitCount[n, #, 0] > 0 &], {n, 3, 120}] (* _Michael De Vlieger_, Mar 10 2016, Version 10 *)
%o A270027 (PARI) a(n) = if (n < 3, 0, my(b=3); while(vecmin(digits(n, b)), b++); b); \\ _Michel Marcus_, Mar 10 2016
%Y A270027 Cf. A069575, A270026, A270028, A216194, A270029, A270030, A270031, A270033, A270034, A270035, A270037.
%K A270027 nonn,base
%O A270027 1,3
%A A270027 _Nathan Fox_, Mar 08 2016