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A175297
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Convert n to binary. AND each respective digit of binary n and binary A030101(n), where A030101(n) is the reversal of the order of the digits in the binary representation of n (given in decimal). a(n) is the decimal value of the result.
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7
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1, 0, 3, 0, 5, 2, 7, 0, 9, 0, 9, 0, 9, 6, 15, 0, 17, 0, 17, 4, 21, 4, 21, 0, 17, 10, 27, 4, 21, 14, 31, 0, 33, 0, 33, 0, 33, 0, 33, 0, 33, 0, 33, 12, 45, 12, 45, 0, 33, 18, 51, 0, 33, 18, 51, 0, 33, 18, 51, 12, 45, 30, 63, 0, 65, 0, 65, 0, 65, 0, 65, 8, 73, 8, 73, 8, 73, 8, 73, 0, 65, 0, 65
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OFFSET
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1,3
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COMMENTS
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By "respective" digits of binary n and binary A030101(n), the rightmost digit of A030101(n) ( which is a 1) is AND'ed with the rightmost digit of n. A030101(n) is represented with the appropriate number of leading 0's.
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LINKS
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EXAMPLE
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20 in binary is 10100. The reversal of the binary digits is 00101. So, from leftmost to rightmost respective digits, we AND 10100 and 00101: 1 AND 0 = 0. 0 AND 0 = 0. 1 AND 1 = 1. 0 AND 0 = 0. And 0 AND 1 = 1. So, 10100 AND 00101 is 100, which is 4 in decimal. So a(20) = 4.
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MATHEMATICA
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Table[f = IntegerDigits[x, 2]; f = f + Reverse[f]; FromDigits[ Table[If[f[[r]] == 2, 1, 0], {r, 1, Length[f]}], 2], {x, 83}] (* Dylan Hamilton, Oct 15 2010 *)
Table[With[{d = IntegerDigits[n, 2]}, FromDigits[#, 2] &@ Map[BitAnd @@ # &, Transpose@{d, Reverse@ d}]], {n, 83}] (* Michael De Vlieger, Sep 03 2017 *)
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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Extended, with redundant initial entries included, by Dylan Hamilton, Oct 15 2010
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STATUS
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approved
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