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Search: id:A138920
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| A138920 |
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Indices k such that A020509(k)=Phi[k](-10) is prime, where Phi is a cyclotomic polynomial. |
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19
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| 4, 5, 7, 12, 19, 24, 31, 36, 38, 46, 48, 53, 67, 75, 78, 120, 186, 196, 293, 320, 327, 369, 634, 641, 713, 770, 931
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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"Unique [period] primes" (A040017) are often of the form Phi[k](10) or Phi[k](-10).
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LINKS
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C. Caldwell, Unique Primes.
Index entries for cyclotomic polynomials, values at X
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PROGRAM
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(PARI) for( i=1, 999, is/*pseudo*/prime( polcyclo(i, -10)) && print1( i", ")) /* for PARI < 2.4.2 use ...subst(polcyclo(i, x), x, -10)... */
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CROSSREFS
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Cf. A019328, A040017, A138940.
Adjacent sequences: A138917 A138918 A138919 this_sequence A138921 A138922 A138923
Sequence in context: A079337 A032390 A112918 this_sequence A048224 A064237 A139373
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KEYWORD
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nonn,more
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AUTHOR
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M. F. Hasler (www.univ-ag.fr/~mhasler), Apr 03 2008
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