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Search: id:A086473
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| A086473 |
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Numbers in A058080 having only one factor pair (both distinct from 1) that add up to a sum belonging to A014092. |
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+0
4
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| 18, 24, 28, 50, 52, 54, 76, 92, 96, 98, 100, 112, 124, 140, 144, 148, 152, 160, 172, 176, 188, 192, 208, 212, 216, 220, 228, 232, 242, 244, 260, 266, 268, 280, 288, 290, 292, 304, 308, 316, 332, 336, 338, 344, 356, 374, 384, 388, 392, 400, 412, 434, 436, 448
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Related to the "Impossible Problem" of Martin Gardner.
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REFERENCES
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M. Criton, "Le Probleme Impossible", Jeux Mathematiques, Tangente Hors Serie No. 20 Pole Paris 2004.
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LINKS
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J. Derbyshire, Product and Sum
N. Hobson, Nick's Mathematical Miscellany, Two Logicians
Dr. Rob, The Math Forum, Two Mathematicians Problem
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EXAMPLE
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A058080(3)=18 is in the sequence because 18=2*9=3*6 and only 2+9=11 belongs to A014092. However, A058080(7)=30 is not in the sequence because 30=2*15=3*10=5*6 with both 2+15 and 5+6 belonging to A014092.
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CROSSREFS
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Cf. A058080, A014092.
Sequence in context: A031407 A002505 A050772 this_sequence A076770 A105679 A076771
Adjacent sequences: A086470 A086471 A086472 this_sequence A086474 A086475 A086476
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KEYWORD
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nonn
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AUTHOR
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Lekraj Beedassy (blekraj(AT)yahoo.com), Sep 09 2003
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EXTENSIONS
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Corrected and extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Sep 21 2003
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