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 A117676 #6 Feb 14 2016 17:44:08 %S A117676 0,1,4,9,36,49,64,81,100,121,144,225,256,289,324,361,400,441,576,625, %T A117676 676,729,784,841,900,1089,1156,1225,1296,1369,1444,1521,1764,1849, %U A117676 1936,2025,2116,2209,2304,2601,2704,2809,2916,3025,3136,3249,3600,3721,3844 %N A117676 Squares for which the digital root is also a square. %H A117676 Harvey P. Dale, <a href="/A117676/b117676.txt">Table of n, a(n) for n = 0..10000</a> %F A117676 Empirical g.f.: -x*(x +1)*(x^12 +2*x^11 +3*x^10 +24*x^9 -11*x^8 +26*x^7 -9*x^6 +26*x^5 -11*x^4 +24*x^3 +3*x^2 +2*x +1) / ((x -1)^3*(x^6 +x^5 +x^4 +x^3 +x^2 +x +1)^2). - _Colin Barker_, Jan 17 2014 %t A117676 drQ[n_]:=IntegerQ[Sqrt[NestWhile[Total[IntegerDigits[#]]&,n,#>9&]]]; Select[Range[0,100]^2,drQ] (* _Harvey P. Dale_, Feb 14 2016 *) %Y A117676 Cf. A000290. %K A117676 nonn,base %O A117676 0,3 %A A117676 Luc Stevens (lms022(AT)yahoo.com), Apr 12 2006