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 A051827 #4 Jun 11 2014 17:24:23
%S A051827 1,4,18,104,770,7188,71267,668712,5784858,46456730,351209716,
%T A051827 2538926040,17934291011,128545882129,994784980860,8902285643456
%N A051827 Number of numbers below 10^n with nonzero multiplicative digital root 7.
%C A051827 Conjectured o(10^n)
%D A051827 William Mayne, sci.math, Jun 15 1991
%F A051827 # { i : 10^(n-1) < i < 10^n and A051802(i)=7 }
%Y A051827 Cf. A051802, A051809, A051818.
%K A051827 nonn,base,hard
%O A051827 1,2
%A A051827 _Dan Hoey_, Dec 09 1999