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A120629
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Numbers n with property that -n is not a perfect power and the squarefree part of -n is not congruent to 1 modulo 4.
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1
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2, 4, 5, 6, 9, 10, 13, 14, 16, 17, 18, 20, 21, 22, 24, 25, 26, 29, 30, 33, 34, 36, 37, 38, 40, 41, 42, 45, 46, 49, 50, 52, 53, 54, 56, 57, 58, 61, 62, 65, 66, 68, 69, 70, 72, 73, 74, 77, 78, 80, 81, 82, 84, 85, 86, 88, 89, 90, 93, 94, 96, 97, 98, 100, 101, 102, 104, 105, 106
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| According to a famous 1927 conjecture of Emil Artin, modified by Dick Lehmer, these negative numbers are primitive roots modulo each prime of a set whose density among primes equals Artin's constant (see A005596). The positive numbers with the same property are given by A085397.
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..1000
G. P. Michon, Artin's Constant.
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EXAMPLE
| -3 and -12 are not in the set because their squarefree parts are equal to -3, which is congruent to 1 modulo 4. -32 is not in the set because it is the fifth power of -2. -1 is excluded because it is an odd power of -1.
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CROSSREFS
| Cf. A085397, A005596.
Sequence in context: A143072 A089648 A062861 * A169694 A015834 A050011
Adjacent sequences: A120626 A120627 A120628 * A120630 A120631 A120632
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KEYWORD
| easy,nice,nonn
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AUTHOR
| Gerard P. Michon (g.michon(AT)att.net), Jun 20 2006
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