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Search: id:A141676
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| A141676 |
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Numbers n such that: Mod[DivisorSigma[0, n]*PrimePi[n], 8] == 0. |
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+0
1
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| 1, 7, 8, 10, 14, 15, 19, 20, 21, 22, 24, 30, 37, 38, 39, 40, 42, 46, 53, 54, 55, 56, 57, 58, 62, 65, 66, 70, 71, 72, 78, 82, 88, 89, 90, 91, 92, 93, 94, 95, 96, 102, 104, 105, 107, 108, 110, 114, 115, 118, 119, 120, 122, 123, 125, 126, 128, 130, 131, 132, 133, 134, 135
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Nearly 50% of all integers fall in this category.
Mod[DivisorSigma[0, n]*PrimePi[n], 8] == 4
is the next biggest category.
I was looking at
a(n)=DivisorSigma[0, n]*PrimePi[n];
and noticed it give a plot with nearly 8 line levels.
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FORMULA
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a(n) =If[Mod[DivisorSigma[0, n]*PrimePi[n], 8] == 0,n]
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MATHEMATICA
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Flatten[Table[If[Mod[DivisorSigma[0, n]*PrimePi[n], 8] == 0, n, {}], {n, 1, 200}]]
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CROSSREFS
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Sequence in context: A067529 A080113 A048588 this_sequence A127164 A153972 A111064
Adjacent sequences: A141673 A141674 A141675 this_sequence A141677 A141678 A141679
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KEYWORD
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nonn,uned
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AUTHOR
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Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Sep 07 2008
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