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A208980
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List of winning positions in Barry Cipra's Factor Subtractor game.
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1
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4, 9, 10, 14, 16, 18, 22, 25, 26, 28, 30, 34, 36, 40, 46, 48, 49, 54, 55, 56, 62, 63, 65, 66, 68, 74, 75, 76, 80, 81, 84, 88, 90, 94, 96, 100, 104, 105, 114, 115, 116, 119, 120, 121, 126, 132, 135, 138, 142, 144, 153, 154, 155, 156, 160, 162, 166, 168, 170, 174, 178, 182, 183, 184, 185, 190, 192, 196, 198, 202, 204
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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COMMENTS
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A positive integer n is in the sequence if and only if it has a proper factorization, n=hk, for which neither n-h nor n-k is in the sequence. (No prime is in the sequence, because no prime has a proper factorization.) [Barry Cipra, Mar 07 2012]
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REFERENCES
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Barry Cipra, Personal communication, Mar 02 2012
Barry Cipra, Factor Subtractor, 2012; reprinted in "Barrycades and Septoku: Papers in Honor of Martin Gardner and Tom Rogers", ed. Thane Plambeck and Tomas Rokicki, MAA Press, 2020, pp. 59-62.
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LINKS
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Matthew Richey, Table of n, a(n) for n = 1..85667
Barry Cipra, Factor Subtractor, 2012
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CROSSREFS
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Sequence in context: A028839 A141833 A140292 * A010426 A243170 A356711
Adjacent sequences: A208977 A208978 A208979 * A208981 A208982 A208983
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane, Mar 04 2012
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STATUS
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approved
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