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A107748
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Number of monic divisors of x^n - 1 with coefficients in {0,1,-1}.
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2
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2, 4, 4, 8, 4, 14, 4, 16, 8, 14, 4, 48, 4, 14, 14, 32, 4, 50, 4, 48, 14, 14, 4, 162, 8, 14, 16, 48, 4, 136, 4, 64, 14, 14, 14, 286, 4, 14, 14, 160, 4, 136, 4, 48, 48, 14, 4, 550, 8, 50, 14, 48, 4, 186, 14, 164, 14, 14, 4, 1124, 4, 14, 48, 128, 14, 136, 4, 48, 14, 136
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Multiply by 2 to get all that have coefficients in {0,1,-1}.
Note that many of these are equal to 2^tau(n), where tau(n) is the number of positive divisors of n = number of irreducible factors of x^n - 1. This is connected with the fact that for small values of n the coefficients of the n-th cyclotomic polynomial belong to {0,1,-1}.
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CROSSREFS
| Cf. A107067, A067824.
Sequence in context: A131136 A117973 A140434 * A005884 A079890 A180444
Adjacent sequences: A107745 A107746 A107747 * A107749 A107750 A107751
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KEYWORD
| nonn
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AUTHOR
| Edwin Clark (eclark(AT)math.usf.edu), Jun 11 2005
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