document.write( "Question 1058638: What's the next number in the series?
\n" ); document.write( "4, 12, 13, 15, 14, 10, 11, 9 ...
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Algebra.Com's Answer #673729 by Alan3354(69443)\"\" \"About 
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What's the next number in the series?
\n" ); document.write( "4, 12, 13, 15, 14, 10, 11, 9 ...
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\n" ); document.write( "It's 8.
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\n" ); document.write( "
\n" ); document.write( "0100 4
\n" ); document.write( "1100 12
\n" ); document.write( "1101 13
\n" ); document.write( "1111 15
\n" ); document.write( "1110 14
\n" ); document.write( "1010 10
\n" ); document.write( "1011 11
\n" ); document.write( "1001 9
\n" ); document.write( "1000 8
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\n" ); document.write( "It's Gray Code, or reflected binary code.
\n" ); document.write( "1 bit changes at each transition.
\n" ); document.write( "For the 4 bits:
\n" ); document.write( "0
\n" ); document.write( "1
\n" ); document.write( "3
\n" ); document.write( "2
\n" ); document.write( "6
\n" ); document.write( "7
\n" ); document.write( "5
\n" ); document.write( "4
\n" ); document.write( "C
\n" ); document.write( "D
\n" ); document.write( "F
\n" ); document.write( "E
\n" ); document.write( "A
\n" ); document.write( "B
\n" ); document.write( "9
\n" ); document.write( "8
\n" ); document.write( "then
\n" ); document.write( "18
\n" ); document.write( "19
\n" ); document.write( "1B
\n" ); document.write( "1A
\n" ); document.write( "1E
\n" ); document.write( "etc.\r
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