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A077647
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Smallest term of a run of at least 8 consecutive integers which are not squarefree.
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11
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1092747, 7216618, 8870024, 8870025, 14379271, 22635347, 24816974, 25047846, 33678771, 33908368, 33908369, 34394371, 34682346, 37923938, 49250144, 49250145, 53379270, 69147868, 69147869, 70918820, 70918821, 71927247, 72913022, 83605071, 85972019, 90571646
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OFFSET
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1,1
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LINKS
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Table of n, a(n) for n=1..26.
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FORMULA
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A077647 = { A077640[k] | A077640[k+1] = A077640[k]+1 }. - M. F. Hasler, Feb 01 2016
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EXAMPLE
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n=8870024: squares dividing n+j (j=0...8) i.e. 9 consecutive integers are as follows {4,25,121,841,4,49,961,9,16}
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MATHEMATICA
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s8[x_] := Apply[Plus, Table[Abs[MoebiusMu[x+j]], {j, 0, 7}]] If[Equal[s, 0], Print[n]], {n, 1000000, 100000000}]
Flatten[Position[Partition[SquareFreeQ/@Range[91000000], 8, 1], _?(Union[#]=={False}&), {1}, Heads->False]]
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PROG
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(PARI) for(n=1, 10^8, forstep(k=7, 0, -1, issquarefree(n+k)&&(n+=k)&&next(2)); print1(n", ")) \\ M. F. Hasler, Feb 03 2016
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CROSSREFS
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Cf. A013929, A051681.
Cf. A045882 (first k-chain), A068781 (2-chains), A070258 (3-chains), A070284 (4-chains), A078144 (5-chains), A049535 (6-chains), A077640 (7-chains), A077647 (8-chains), A078143 (9-chains), A268313 (10-chains), A268314 (11-chains).
Sequence in context: A224592 A252119 A109148 * A172647 A172754 A268036
Adjacent sequences: A077644 A077645 A077646 * A077648 A077649 A077650
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KEYWORD
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nonn
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AUTHOR
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Labos Elemer, Nov 18 2002
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STATUS
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approved
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