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A336371
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Numbers k such that gcd(k, prime(k) + prime(k-1)) > 1.
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4
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4, 6, 8, 9, 10, 12, 13, 14, 15, 16, 18, 20, 21, 22, 24, 26, 27, 28, 30, 32, 34, 36, 38, 39, 40, 42, 44, 45, 46, 48, 50, 51, 52, 54, 56, 57, 58, 60, 62, 63, 64, 65, 66, 68, 69, 70, 72, 74, 76, 78, 80, 81, 82, 84, 86, 88, 90, 92, 93, 94, 95, 96, 98, 99, 100
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OFFSET
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1,1
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LINKS
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FORMULA
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In the following table, p(k) = A000040(k) = prime(k).
k p(k) p(k)+p(k-1) gcd
2 3 5 1
3 5 8 1
4 7 12 4
5 11 18 1
6 13 24 6
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MATHEMATICA
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p[n_] := Prime[n];
u = Select[Range[2, 200], GCD[#, p[#] + p[# - 1]] == 1 &] (* A336370 *)
v = Select[Range[2, 200], GCD[#, p[#] + p[# - 1]] > 1 &] (* A336371 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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