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A124569
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Numbers n such that n, n+2, n+4 and n+6 are squarefree.
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2
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1, 11, 13, 15, 17, 29, 31, 33, 35, 37, 51, 53, 55, 65, 67, 83, 85, 87, 89, 91, 101, 103, 105, 107, 109, 127, 137, 139, 155, 157, 159, 161, 177, 179, 181, 191, 193, 195, 197, 199, 209, 211, 213, 215, 217, 227, 229, 231, 233, 235, 247, 249, 251, 253, 263, 265, 267
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OFFSET
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1,2
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COMMENTS
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Numbers n, n+2, n+4 and n+6 are four successive odd squarefree numbers.
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LINKS
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Robert Israel, Table of n, a(n) for n = 1..10000
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MAPLE
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filter:= proc(n) andmap(numtheory:-issqrfree, [n, n+2, n+4, n+6]) end proc:
select(filter, [seq(i, i=1..1000, 2)]); # Robert Israel, Jun 08 2021
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PROG
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(PARI) isok(n) = issquarefree(n) && issquarefree(n+2) && issquarefree(n+4) && issquarefree(n+6); \\ Michel Marcus, Oct 11 2013
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CROSSREFS
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Cf. A007675, A024556.
Sequence in context: A152200 A277694 A179084 * A260826 A289699 A049722
Adjacent sequences: A124566 A124567 A124568 * A124570 A124571 A124572
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KEYWORD
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nonn
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AUTHOR
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Zak Seidov, Dec 27 2006
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STATUS
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approved
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