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Search: id:A161818
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| A161818 |
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If b(n) = the largest proper divisor of n, then a(n) = (2^n -1)/(2^b(n) -1). |
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1
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| 3, 7, 5, 31, 9, 127, 17, 73, 33, 2047, 65, 8191, 129, 1057, 257, 131071, 513, 524287, 1025, 16513, 2049, 8388607, 4097, 1082401, 8193, 262657, 16385, 536870911, 32769, 2147483647, 65537, 4196353, 131073, 270549121, 262145, 137438953471, 524289
(list; graph; listen)
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OFFSET
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2,1
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EXAMPLE
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a(6)=(2^6-1)/(2^3-1)=63/7=9. [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 26 2009]
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MAPLE
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with(numtheory): a := proc (n) options operator, arrow: (2^n-1)/(2^divisors(n)[tau(n)-1]-1) end proc: seq(a(n), n = 2 .. 40); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 26 2009]
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CROSSREFS
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A032742
Sequence in context: A064078 A048857 A005420 this_sequence A161509 A108974 A106853
Adjacent sequences: A161815 A161816 A161817 this_sequence A161819 A161820 A161821
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet (q1qq2qqq3qqqq(AT)yahoo.com), Jun 20 2009
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EXTENSIONS
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Extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 26 2009
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