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Search: id:A046693
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| A046693 |
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Size of smallest subset S of N={0,1,2,...,n} such that S-S=N, where S-S={abs(i-j) | i,j in S}. |
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+0
1
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| 1, 2, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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It is easy to show that a(n+1) must be no larger than a(n)+1. Problem: Can a(n+1) ever be smaller than a(n)?
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REFERENCES
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Related to 'The set of differences of a given set', by Andrew Granville and Friedrich Roesler, Amer. Math. Monthly, 106 (1999), 338-344.
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LINKS
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A. Granville and F. Roesler, The set of differences of a given set
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EXAMPLE
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a(10)=6, since all integers in {0,1,2...10} are differences of elements of {0,1,2,3,6,10}, but not of any 5-element set.
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CROSSREFS
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Sequence in context: A083398 A061420 A003057 this_sequence A058889 A110862 A104257
Adjacent sequences: A046690 A046691 A046692 this_sequence A046694 A046695 A046696
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KEYWORD
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nonn
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AUTHOR
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Johm W. Layman (layman(AT)math.vt.edu)
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