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 A235001 #8 Jan 14 2014 10:18:25 %S A235001 1,4,16,25,49,64,81,100,121,196,256,289,324,361,400,484,529,625,784, %T A235001 841,961,1024,1089,1156,1225,1296,1444,1521,1600,1681,1849,1936,2116, %U A235001 2401,2500,2601,3025,3136,3364,3481,3844,4096,4225,4356,4489,4624,4900,5041,5184,5625 %N A235001 Odious squares. %C A235001 This sequence is the intersection of A000069 and A000290. Numbers n^2 such that A159918 is odd. %H A235001 Harvey P. Dale, <a href="/A235001/b235001.txt">Table of n, a(n) for n = 1..1000</a> %e A235001 16 is a square 4^2 and 16 in base 2 is a 10000, having an odd number of 1's, thus 16 is in this sequence. %t A235001 Select[Range[200]^2,OddQ[DigitCount[#,2,1]]&] (* _Harvey P. Dale_, Jan 14 2014 *) %Y A235001 Cf. A231431 (evil squares). %K A235001 nonn %O A235001 1,2 %A A235001 _Gerasimov Sergey_, Jan 02 2014