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A070195
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Squarefree numbers sandwiched between a pair of twin primes.
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4
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6, 30, 42, 102, 138, 282, 462, 570, 618, 642, 822, 858, 1230, 1290, 1302, 1482, 1698, 1722, 1878, 2082, 2130, 2238, 2310, 2382, 2658, 2730, 2802, 3390, 3462, 3558, 3918, 3930, 4002, 4218, 4242, 4422, 4638, 4722, 5010, 5442, 5478, 5502, 5658, 6090, 6198
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OFFSET
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1,1
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COMMENTS
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Numbers k such that k is squarefree, k-1 and k+1 are primes.
All terms are multiples of 6. - Zak Seidov, Mar 20 2016
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LINKS
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MAPLE
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select(t -> numtheory:-issqrfree(t) and isprime(t+1) and isprime(t-1),
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MATHEMATICA
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Select[12 * Range[0, 500] + 6, PrimeQ[#-1] && PrimeQ[#+1] && SquareFreeQ[#] &] (* Amiram Eldar, May 23 2022 *)
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PROG
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(PARI) {forstep(n=6, 8000, 12, if(issquarefree(n)&&isprime(n-1)&&isprime(n+1), print1(n", "))); } \\ Zak Seidov, Mar 20 2016
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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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