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Search: id:A055035
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| A055035 |
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Degree of minimal polynomial of sin(pi/n) over the rationals. |
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+0
2
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| 1, 1, 2, 2, 4, 1, 6, 4, 6, 2, 10, 4, 12, 3, 8, 8, 16, 3, 18, 8, 12, 5, 22, 8, 20, 6, 18, 12, 28, 4, 30, 16, 20, 8, 24, 12, 36, 9, 24, 16, 40, 6, 42, 20, 24, 11, 46, 16, 42, 10, 32, 24, 52, 9, 40, 24, 36, 14, 58, 16, 60, 15, 36, 32, 48, 10, 66, 32, 44, 12, 70, 24, 72
(list; graph; listen)
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OFFSET
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1,3
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LINKS
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Eric Weisstein's World of Mathematics, Trigonometry Angles
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FORMULA
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a(1)=1, a(2)=1, a(n)=phi(n)/(1, 1, 2, 1 for n=0, 1, 2, 3 mod 4) for n>2,
where phi is Euler's totient, A000010.
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MATHEMATICA
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a[n_] := If[n==2, 1, EulerPhi[n]/{1, 1, 2, 1}[[Mod[n, 4]+1]]];
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CROSSREFS
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Cf. A000010.
Sequence in context: A072211 A070306 A014665 this_sequence A152593 A105478 A114427
Adjacent sequences: A055032 A055033 A055034 this_sequence A055036 A055037 A055038
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KEYWORD
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easy,nonn
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AUTHOR
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Shawn Cokus (Cokus(AT)math.washington.edu)
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