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Search: id:A154611
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| A154611 |
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Numbers n such that 7n+3 is not prime. |
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+0
1
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| 1, 3, 5, 6, 7, 9, 11, 12, 13, 15, 16, 17, 18, 19, 20, 21, 23, 24, 25, 26, 27, 29, 30, 31, 33, 35, 36, 37, 39, 41, 42, 43, 45, 46, 47, 48, 49, 51, 53, 54, 55, 56, 57, 59, 60, 61, 62, 63, 64, 65, 66, 67, 69, 70, 71, 72, 73, 75, 76, 77, 78, 79
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Of course n is odd.
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FORMULA
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Let p prime number, n=[(p^2+2p-3)/7] mod (p); or, n=[(p^2+4p-3)/7] mod (p); or, n=[(p^2+12p-3)/7] mod (p).
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EXAMPLE
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Example: 42=[11^2+2*11-3)/7]mod (11), 42=20 mod(11); 26=[(5^2+4*5-3)/7] mod (5), 26=6 mod (5); 18=[(3^2+12*3-3)/7] mod (3), 18=6 mod (3)
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CROSSREFS
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Cf. A089033, A045437, A017017
Sequence in context: A161373 A103826 A079905 this_sequence A164028 A047273 A064802
Adjacent sequences: A154608 A154609 A154610 this_sequence A154612 A154613 A154614
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KEYWORD
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nonn
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AUTHOR
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Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Jan 15 2009
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