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 A137578 #5 Mar 30 2012 18:50:59
%S A137578 0,0,0,0,0,3,1,1,1,1,1,2,2,1,3,2,1,1,1,7,5,3,3,1,5,6,7,2,2,2,7,3,4,2,
%T A137578 1,8,5,8,8,5,3,9,2,4,9,8,3,7,9,9,5,4,1,1,5,7,2,3,6,5,5,1,4,5,7,1,5,3,
%U A137578 6,6,3,4,5,9,6,3,1,5,9,4,9,3,5,8,4,8,1,6,7,4,2,3,9,9,9,1,2,4,1,7,7
%N A137578 Smallest of the least frequent digits in decimal representation of n!.
%C A137578 a(n) <= A137577(n).
%H A137578 <a href="/index/Fa#factorial">Index entries for sequences related to factorial numbers</a>.
%e A137578 n=10: 10! = 3628800 => a(10) = Min{1,4,5,7,9} = 1;
%e A137578 n=11: 11! = 39916800 => a(11) = Min{2,4,5,7} = 2.
%Y A137578 Cf. A000142, A027869, A079680, A079714, A079684, A079688, A079690, A079691, A079692, A079693, A079694, A137579, A137580.
%K A137578 nonn,base
%O A137578 0,6
%A A137578 _Reinhard Zumkeller_, Jan 27 2008