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Search: id:A067139
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| A067139 |
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Irreducible elements in OR-numbral arithmetic. |
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+0
8
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| 1, 2, 3, 5, 9, 11, 13, 17, 19, 23, 25, 29, 33, 35, 37, 39, 41, 43, 49, 53, 57, 65, 67, 69, 71, 75, 77, 79, 81, 83, 87, 89, 93, 97, 101, 105, 107, 113, 117, 121, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151, 157, 159, 161, 163, 167, 169, 171, 177, 179
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Numbers n such that there is no number d in range 1 < d < n with d*k = n for any 1 < k < n, where * is defined in A066376.
See A048888 for the definition of OR-numbral arithmetic. Note that 2 is the only prime element in OR-numbral arithmetic; for all other non-unit irreducibles x there exist numbers a and b not divisible by x such that x is a divisor of a * b.
Numbers n such that A066376(n) = 1.
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REFERENCES
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A. Frosini and S. Rinaldi, On the Sequence A079500 and Its Combinatorial Interpretations, Journal of Integer Sequences, Vol. 9 (2006), Article 06.3.1.
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CROSSREFS
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Cf. A003986, A067138, A048888, A007059.
Sequence in context: A058108 A056144 A078645 this_sequence A014657 A161514 A140329
Adjacent sequences: A067136 A067137 A067138 this_sequence A067140 A067141 A067142
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KEYWORD
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nonn,nice
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AUTHOR
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Jens Voss (jens.voss(AT)poet.de), Jan 02 2002
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com) at the suggestion of Andrew Plewe and Joshua Zucker, Jun 12 2007
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