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 A204574 #5 Mar 30 2012 17:23:05 %S A204574 0,1,11,10001,1100011,1001000001,110100100011,100110010010001, %T A204574 11011111001000011,10100010100100000001,1110110011011111000011, %U A204574 1010110010010010110010001,111110110111010100110100011,101101110011001101010001000001 %N A204574 Numbers such that floor[a(n)^2/2] is a square (A001541), written in binary. %Y A204574 See also A031149=sqrt(A023110) (base 10), A204502=sqrt(A204503) (base 9), A204514=sqrt(A055872) (base 8), A204516=sqrt(A055859) (base 7), A204518=sqrt(A055851) (base 6), A204520=sqrt(A055812) (base 5), A004275=sqrt(A055808) (base 4), A001075=sqrt(A055793) (base 3), A001541=sqrt(A055792) (base 2). %K A204574 nonn,base %O A204574 1,3 %A A204574 _M. F. Hasler_, Jan 16 2012