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 A109072 #11 Feb 23 2017 22:20:44
%S A109072 0,0,1,1,1,0,0,1,1,1,0,0,1,1,1,1,1,2,2,1,1,1,2,1,2,0,1,0,1,2,1,1,1,2,
%T A109072 2,1,1,1,2,2,1,1,1,1,2,1,1,2,1,1,0,1,1,2,2,0,1,2,2,2,0,1,2,0,0,1,0,2,
%U A109072 1,1,1,1,2,1,0,1,0,2,1,2,1,1,1,1,2,1,1,1,2,1,1,1,2,1,2,0,0,1,1,0,0,0,1,1,1
%N A109072 Number of decimal digits ( counted with multiplicity ) in n but not in n^2.
%H A109072 Robert Israel, <a href="/A109072/b109072.txt">Table of n, a(n) for n = 0..10000</a>
%p A109072 f:= proc(n) local L2;
%p A109072 L2:= convert(n^2,base,10);
%p A109072 nops(remove(t -> member(t,L2), convert(n,base,10)));
%p A109072 end proc:
%p A109072 map(f, [$0..200]); # _Robert Israel_, Feb 22 2017
%t A109072 UnsortedComplement[x_List, y__List]:=Replace[x, Dispatch[(#\[RuleDelayed]Sequence[])&/@Union[y]], 1]; Table[Length[UnsortedComplement[IntegerDigits[n], IntegerDigits[n^2]]], {n, 0, 200}]
%Y A109072 Cf. A076493 (number of common and distinct decimal digits of n and n^2).
%Y A109072 Cf. A109071 (number of common decimal digits (counted with multiplicity) of n and n^2).
%K A109072 base,easy,nonn
%O A109072 0,18
%A A109072 _Zak Seidov_, Jun 20 2005