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A319502
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Indices of Mertens's function M(n) (A002321) whose nearest neighbors have value 0.
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0
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165, 237, 330, 354, 357, 365, 402, 406, 421, 426, 794, 797, 813, 885, 894, 897, 905, 914, 1257, 1281, 1290, 1298, 1301, 1337, 1522, 1526, 1545, 1842, 1865, 2094, 2098, 2118, 2121, 2137, 4602, 4609, 4621, 4629, 4726, 4729, 4738, 5106, 5109, 5198, 5206, 5221
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OFFSET
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1,1
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COMMENTS
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This sequence records the shortest intervals where M(n) leaves 0 before returning to 0.
a(n) - 1 and a(n) + 1 are both terms of A028442.
Both A045882 and A028442 are infinite and this allows for the possibility that this sequence is also infinite (for A028442 see comment of A002321).
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LINKS
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FORMULA
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EXAMPLE
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MAPLE
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with(numtheory): a:=n->add(mobius(k), k=1..n): select(n->a(n-1)=0 and a(n+1)=0, [$2..2200]); # Muniru A Asiru, Sep 20 2018
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MATHEMATICA
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With[{s = Partition[Accumulate@ Array[MoebiusMu, 5300], 3, 1]}, 1 + First /@ Position[s, {0, k_, 0} /; k != 0]] (* Michael De Vlieger, Sep 24 2018 *)
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PROG
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(PARI) isok(n) = {if (n > 1, x = sum(k=1, n-1, moebius(k)); if (x == 0, if (x + moebius(n) + moebius(n+1) == 0, return (1)); ); ); return (0); } \\ Michel Marcus, Sep 27 2018
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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