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 A238712 #20 Feb 27 2015 23:26:44
%S A238712 0,1,4,5,6,9,16,21,24,25,29,36,41,44,49,56,61,64,69,76,81,84,89,96,
%T A238712 100,104,116,121,124,129,136,144,156,161,164,169,176,184,196,201,204,
%U A238712 209,216,224,225,236,241,244,249,256,264,276,281,284,289,296,304
%N A238712 Numbers in which squares may end (in base 10).
%C A238712 The union of "squares mod 10" (= the first 6 terms) and "squares mod 100" (A010461) and "squares mod 1000" (A122986) etc.
%C A238712 The number of terms < 10^k beginning with k=0: 1, 6, 24, 165, 1101, 9306, 79620, 753462, 7198791, 70919559, ... - _Robert G. Wilson v_, Sep 04 2014
%H A238712 Derek Orr, <a href="/A238712/b238712.txt">Table of n, a(n) for n = 1..9306</a>
%F A238712 If n is present so is n^2. - _Robert G. Wilson v_, Sep 04 2014
%e A238712 6 is in the sequence because 4^2 = 16 ends in the digit 6.
%e A238712 7 is not in the sequence because no square can end with the digit 7.
%t A238712 mx = 3; t = Union@ Table[ Mod[n^2, 10^mx], {n, 10^mx/2}]; t = Union@ Flatten@ Table[ Mod[t, 10^m], {m, mx}] (* _Robert G. Wilson v_, Sep 04 2014 *)
%o A238712 (PARI) a=[];for(m=1,3,a=setunion(a,Set(vector(10^m,n,n^2)%10^m)));a
%Y A238712 Cf. A161355, A246422, A246448 (Complement).
%K A238712 nonn,base
%O A238712 1,3
%A A238712 _M. F. Hasler_, Mar 03 2014