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%I #28 Nov 22 2023 08:01:56
%S 0,1,11,10,110,111,101,100,1100,1101,1111,1110,1010,1011,1001,1000,
%T 11000,11001,11011,11010,11110,11111,11101,11100,10100,10101,10111,
%U 10110,10010,10011,10001,10000,110000,110001,110011,110010,110110
%N Binary reflected Gray code.
%D Gardner, M. "The Binary Gray Code." Ch. 2 in Knotted Doughnuts and Other Mathematical Entertainments. New York: W. H. Freeman, 1986.
%D C. A. Pickover, The Math Book, Sterling, NY, 2009; see p. 392.
%H Alois P. Heinz, <a href="/A014550/b014550.txt">Table of n, a(n) for n = 0..8191</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/GrayCode.html">Gray Code</a>
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Gray_code">Gray code</a>
%p a:= proc(n) option remember; `if`(n<2, n,
%p (b-> 10^b +a(2^(b+1)-1-n))(ilog2(n)))
%p end:
%p seq(a(n), n=0..50); # _Alois P. Heinz_, Nov 01 2008
%t a[n_] := a[n] = (b = Floor[Log[2, n]]; If[n <= 1, n, 10^b + a[2^(b + 1) - 1 - n]]); Table[a[n], {n, 0, 36}] (* _Jean-François Alcover_, Oct 11 2012, after _Alois P. Heinz_ *)
%o (PARI) a(n)=fromdigits(binary(bitxor(n, n>>1))) \\ _Charles R Greathouse IV_, Feb 06 2017
%Y Same sequence in decimal: A003188.
%K nonn,nice,easy
%O 0,3
%A _Eric W. Weisstein_
%E More terms from Larry Reeves (Larryr(AT)acm.org), Sep 05 2000
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