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Search: id:A161601
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| A161601 |
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Positive integers n that are each less than the value of the reversal of n's representation in binary. |
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+0
3
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| 11, 19, 23, 35, 37, 39, 43, 47, 55, 67, 69, 71, 75, 77, 79, 83, 87, 91, 95, 103, 111, 131, 133, 135, 137, 139, 141, 143, 147, 149, 151, 155, 157, 159, 163, 167, 171, 173, 175, 179, 183, 187, 191, 199, 203, 207, 215, 223, 239, 259, 261, 263, 265, 267, 269, 271
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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By "reversal" of n's representation in binary, it is meant: write n in binary (without its leading 0's) from most significant digits on the right and least significant digits on the left, instead of writing n from left to right as is usual. Then interpret the new integer by reading it from left to right.
This sequence contains only odd integers.
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EXAMPLE
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37 in binary is 100101. Its digital reversal is 101001, which is 41 in decimal. Since 41 > 37, then 37 is in this sequence.
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MAPLE
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a := proc (n) local n2, sz, rv: n2 := convert(n, base, 2): sz := nops(n2): rv := add(n2[j]*2^(sz-j), j = 1 .. sz): if n < rv then n else end if end proc; seq(a(n), n = 1 .. 280); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 28 2009]
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CROSSREFS
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A030101, A006995, A161602, A161603
Sequence in context: A161504 A165947 A129517 this_sequence A031406 A105908 A084654
Adjacent sequences: A161598 A161599 A161600 this_sequence A161602 A161603 A161604
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KEYWORD
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base,nonn
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AUTHOR
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Leroy Quet (q1qq2qqq3qqqq(AT)yahoo.com), Jun 14 2009
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EXTENSIONS
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Extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 28 2009
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