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 A232245 #9 Nov 22 2013 14:23:21
%S A232245 0,2,2,4,2,5,4,6,2,5,5,8,4,7,6,8,2,5,5,8,5,9,8,7,4,8,7,10,6,9,8,10,2,
%T A232245 5,5,8,5,9,8,11,5,8,9,11,8,12,7,9,4,8,8,9,7,12,10,12,6,10,9,12,8,11,
%U A232245 10,12,2,5,5,8,5,9,8,11,5,9,9,13,8,11,11,10,5,9
%N A232245 Sum of the number of ones in binary representation of n and n^2.
%C A232245 The sequence is never 1 or 3, but seems to take on all other values. The fact it is never 3 can be used to prove if n^2 has exactly 4 1's then it must have an even number of 0's (A231898).
%F A232245 a(n) = A159918(n) + A000120(n).
%e A232245 5 is 101 and 25 is 11001, so a(5) = 2 + 3 = 5.
%o A232245 (JavaScript)
%o A232245 function bitCount(n) {
%o A232245 var i,c,s;
%o A232245 c=0;
%o A232245 s=n.toString(2);
%o A232245 for (i=0;i<s.length;i++) if (s.charAt(i)==1) c++;
%o A232245 return c;
%o A232245 }
%o A232245 for (i=0;i<100;i++) document.write(bitCount(i*i)+bitCount(i)+", ");
%Y A232245 Cf. A000120, A159918, A077436, A094694, A231898, A232243.
%K A232245 nonn,base
%O A232245 0,2
%A A232245 _Jon Perry_, Nov 20 2013