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A214721
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Least m>0 such that 2*n+1+m and n-m are not relatively prime.
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1
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1, 2, 1, 4, 1, 6, 1, 3, 1, 10, 1, 12, 1, 14, 1, 2, 1, 3, 1, 20, 1, 22, 1, 24, 1, 26, 1, 3, 1, 2, 1, 32, 1, 34, 1, 36, 1, 3, 1, 7, 1, 42, 1, 2, 1, 46, 1, 3, 1, 50, 1, 52, 1, 54, 1, 4, 1, 2, 1, 60, 1, 7, 1, 64, 1, 66, 1, 3, 1, 70, 1, 2, 1, 74, 1, 76, 1, 3, 1, 80, 1
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OFFSET
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1,2
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LINKS
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EXAMPLE
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gcd(17,7) = 1, gcd(19,6) = 1, gcd(20,5) = 5, so a(8) = 3.
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MATHEMATICA
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Table[m = 1; While[GCD[2n+1+m, n - m] != 1, m++]; m, {n, 1, 140}]
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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