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 A204503 #23 Jul 10 2015 20:11:45 %S A204503 0,1,4,9,16,36,81,144,225,324,441,576,729,900,1089,1296,1521,1764, %T A204503 2025,2304,2601,2916,3249,3600,3969,4356,4761,5184,5625,6084,6561, %U A204503 7056,7569,8100,8649,9216,9801,10404,11025,11664,12321,12996,13689,14400,15129,15876 %N A204503 Squares n^2 such that floor(n^2/9) is again a square. %C A204503 Or: Squares which remain squares when their last base-9 digit is dropped. %C A204503 (For the first three terms, which have only 1 digit in base 9, dropping that digit is meant to yield zero.) %C A204503 Base-9 analog of A055792 (base 2), A055793 (base 3), A055808 (base 4), A055812 (base 5), A055851 (base 6), A055859 (base 7), A055872(base 8) and A023110 (base 10). %H A204503 M. F. Hasler, <a href="/wiki/M._F._Hasler/Truncated_squares">Truncated squares</a>, OEIS wiki, Jan 16 2012 %H A204503 <a href="/index/Sq#sqtrunc">Index to sequences related to truncating digits of squares</a>. %F A204503 a(n) = A204502(n)^2. %F A204503 Conjectures: a(n) = 9*(n-4)^2 for n>5. G.f.: x^2*(7*x^6-12*x^5-11*x^4-x-1) / (x-1)^3. - _Colin Barker_, Sep 15 2014 %t A204503 Select[Range[0,200]^2,IntegerQ[Sqrt[Floor[#/9]]]&] (* _Harvey P. Dale_, Jan 27 2012 *) %o A204503 (PARI) b=9;for(n=1,200,issquare(n^2\b) & print1(n^2,",")) %K A204503 nonn,base %O A204503 1,3 %A A204503 _M. F. Hasler_, Jan 15 2012