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A135502
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Admirable numbers in the middle of twin primes.
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1
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12, 30, 42, 102, 138, 270, 282, 618, 642, 822, 1488, 1698, 1878, 2082, 2238, 2382, 2658, 2802, 3462, 3558, 3918, 4638, 4722, 5442, 6198, 6702, 8538, 8598, 9678, 10938, 12162, 12378, 12822, 12918, 13218, 13722, 13758, 13998, 14082, 16062, 17418
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OFFSET
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1,1
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COMMENTS
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Numbers n such that n is admirable, n-1 is prime and n+1 is prime.
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LINKS
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FORMULA
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EXAMPLE
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30 is in the sequence, as 29=30-1 and 31=30+1 are a pair of twin primes.
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MATHEMATICA
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Select[Range[18000], MemberQ[Most[Divisors[#]], (DivisorSigma[1, #]-2#)/2]&&AllTrue[#+{1, -1}, PrimeQ]&] (* Harvey P. Dale, Sep 11 2023 *)
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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