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A332489
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Least positive integer k such that cos(n*k)*cos(n*k + k) < 0.
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2
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1, 2, 1, 2, 1, 5, 2, 2, 1, 1, 1, 2, 3, 1, 1, 1, 2, 1, 10, 1, 2, 1, 2, 1, 11, 1, 2, 1, 1, 1, 3, 2, 2, 1, 1, 2, 2, 5, 1, 2, 1, 2, 1, 88, 1, 2, 1, 2, 1, 5, 2, 2, 1, 1, 1, 2, 3, 1, 1, 1, 2, 1, 9, 1, 2, 1, 2, 1, 13, 1, 2, 1, 1, 1, 3, 2, 2, 1, 1, 2, 2, 4, 1, 2, 1
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OFFSET
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1,2
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COMMENTS
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a(n) = least positive integer k such that cos(n*k) and cos(n*k + k) have opposite signs.
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LINKS
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EXAMPLE
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The signs of cos(6), cos(12), ..., sin(36) are indicated by + + + + + -; that's five +'s followed by -, so that a(6) = 5.
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MATHEMATICA
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Table[First[Map[Length, Split[Table[Sign[Cos[k n]], {k, 1, 500}]]]], {n, 1, 100}]
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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