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A214056
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Least m>0 such that 2^n+m and n-m have a common divisor > 1.
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4
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1, 2, 3, 2, 5, 1, 1, 2, 9, 2, 11, 2, 1, 2, 15, 2, 3, 2, 1, 2, 8, 2, 23, 2, 1, 1, 2, 2, 29, 2, 1, 2, 3, 2, 35, 2, 1, 2, 39, 2, 41, 2, 1, 2, 1, 1, 2, 2, 1, 2, 14, 1, 2, 2, 1, 2, 57, 2, 3, 2, 1, 2, 63, 2, 65, 1, 1, 2, 6, 2, 6, 2, 1, 2, 75, 2, 77, 2, 1, 2, 81, 2
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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(2^4+1,4-1) = 1 and gcd(2^4+2,4-2) = 2, so a(4) = 2.
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MATHEMATICA
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b[n_] := 2^n; c[n_] := n;
Table[m = 1; While[GCD[b[n] + m, c[n] - m] == 1, m++]; m, {n, 1, 100}]
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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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