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 A066330 #8 Feb 03 2020 15:25:08 %S A066330 0,1,10,11,100,1000,1001,1010,1011,1100,1101,1110,1111,-1,-1,-1,10000, %T A066330 10001,10010,10011,10100,11000,11001,11010,11011,11100,11101,11110, %U A066330 11111,-1,-1,-1,100000,100001,100010,100011,100100,101000,101001,101010,101011,101100,101101,101110,101111,-1,-1,-1 %N A066330 Binary string which equals n when 1's, 2's, 4's and 8's bits have weights 1, 2, 4, 5 respectively, while the other bits have their usual weights. -1 if no such string exists. %C A066330 There are engineering reasons for this encoding, but it is unsatisfactory from a mathematical point of view since 5 could equally well be 101. %D A066330 John M. Yarbrough, Digital Logic Applications and Design, West Publishing, 1997, p. 26 %Y A066330 Cf. A066335, A066338. %K A066330 sign,base %O A066330 0,3 %A A066330 _George E. Antoniou_, Dec 15 2001 %E A066330 More terms from _Joshua Zucker_, Jun 21 2006