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A227843
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Numbers n such that the binary XOR of the divisors of n (A178910(n)) is a binary repunit (A000225).
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2
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1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 2592, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 2458624, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824, 2147483648, 4294967296, 8589934592
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OFFSET
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1,2
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COMMENTS
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These are also numbers n such that A178910(n) >= A178910(i) for all i<n.
All powers of 2 are in the sequence. Terms that are not 2^x are 2592 and 2458624. No other non-2^x terms below 2^35.
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LINKS
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MATHEMATICA
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fQ[n_] := Union@ IntegerDigits[ Fold[ BitXor[#1, #2] &, 0, Divisors@ n], 2] == {1}; Select[ Range@ 1000000000, fQ] (* Robert G. Wilson v, Aug 22 2013 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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