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A239291
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Smallest k > 0 such that the products of the nonempty subsets of {k, k+1,..., k+n-1} are all distinct.
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0
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1, 2, 2, 2, 3, 4, 5, 7, 9, 16, 16, 22, 22, 34, 37, 46, 46, 57, 71, 79, 81, 103, 103, 106
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OFFSET
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1,2
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LINKS
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FORMULA
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EXAMPLE
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a(5) = 3 because the range {1,...,5} is ruled out by 1*2=2, the range {2,...,6} by 2*3 = 6 and all 31 subsets of {3,...,7} give a distinct product.
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MATHEMATICA
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a[1]=1; a[n_] := a[n] = Block[{k = a[n-1]}, While[Min@ Differences@ Sort[Times @@@ Rest@ Subsets@ Range[k, n+k-1]] == 0, k++]; k]; Array[a, 16]
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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