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A214069
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Least m>0 such that prime(n)+m and n-m are relatively prime.
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1
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2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 6, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 4, 2, 4, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 2, 6, 1, 2, 1, 2, 2, 6, 1, 2, 2, 2, 1, 4, 1, 2, 1, 2, 2, 4, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 4, 1, 2, 1, 2
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OFFSET
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1,1
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LINKS
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EXAMPLE
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gcd(12,10) = 2 and gcd(13,9) = 1, so that a(11) = 2.
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MATHEMATICA
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Table[m = 1; While[GCD[Prime[n] + m, n - m] != 1, m++]; m, {n, 1, 140}]
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PROG
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(PARI) vector(100, n, m=1; while(gcd(prime(n)+m, n-m)!=1, m++); m) \\ Derek Orr, May 30 2015
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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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