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A060210
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Largest prime factor of 1+smaller term of twin primes.
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6
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2, 3, 3, 3, 5, 7, 5, 3, 17, 3, 23, 5, 5, 3, 11, 19, 5, 5, 47, 13, 29, 7, 3, 11, 29, 19, 5, 103, 107, 11, 5, 137, 23, 13, 7, 17, 43, 7, 59, 13, 3, 41, 71, 43, 31, 11, 17, 11, 19, 31, 67, 5, 139, 283, 41, 149, 13, 313, 23, 13, 37, 13, 347, 29, 11, 71, 17, 373, 7, 11, 13, 397, 17
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OFFSET
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1,1
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COMMENTS
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Also: Largest prime factor of the average, or the sum, of twin prime pairs. - M. F. Hasler, Jan 03 2011
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LINKS
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T. D. Noe, Table of n, a(n) for n = 1..10000
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EXAMPLE
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101 is the 9th lesser twin, 102 = 2*3*17, and its max p factor is 17=a(9).
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MATHEMATICA
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FactorInteger[1+#][[-1, 1]]&/@Select[Partition[Prime[Range[500]], 2, 1], #[[2]]- #[[1]]==2&][[All, 1]] (* Harvey P. Dale, Jan 16 2017 *)
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PROG
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(PARI) p=3; for(n=1, 1e3, until(o+2==p, p=nextprime(2+o=p)); print1(vecmax(factor(p-1)[, 1])", ")) \\ M. F. Hasler, Jan 03 2011
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CROSSREFS
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Cf. A001359, A001454, A002822, A059960, A027856.
Sequence in context: A029065 A263253 A162157 * A260460 A000025 A036020
Adjacent sequences: A060207 A060208 A060209 * A060211 A060212 A060213
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KEYWORD
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nonn
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AUTHOR
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Labos Elemer, Mar 20 2001
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STATUS
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approved
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