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Search: id:A130061
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| A130061 |
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Numbers n such that n divides 3^((n-1)/2) - 2^((n-1)/2) - 1. |
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+0
4
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| 1, 3, 35, 147, 195, 219, 291, 399, 579, 583, 723, 939, 1011, 1023, 1227, 1299, 1371, 1443, 1731, 1803, 2019, 2307, 2499, 2811, 3003, 3027, 3099, 3387, 3459, 3603, 3747, 3891, 3963, 4467, 4623, 4827, 4971, 5187, 5259, 5331, 5403, 5619, 5979, 6051, 6267
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OFFSET
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1,2
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COMMENT
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It appears that all terms are composite except a(1) = 1 and a(2) = 3. Most listed terms are divisible by 3, except {1, 35, 583, 70643, ...}.
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MATHEMATICA
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Select[ Range[10000], Mod[ PowerMod[3, (#-1)/2, # ] - PowerMod[2, (#-1)/2, # ] -1, # ]==0&]
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CROSSREFS
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Cf. A097934 = Primes p such that p divides 3^((p-1)/2) - 2^((p-1)/2). Cf. A038876(n) = Primes p such that 6 is a square mod p. Cf. A127071, A127072, A127073, A127074. Cf. A130058, A130059, A130060, A130062, A130063.
Sequence in context: A113854 A076376 A133710 this_sequence A061548 A019273 A069448
Adjacent sequences: A130058 A130059 A130060 this_sequence A130062 A130063 A130064
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KEYWORD
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nonn
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AUTHOR
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Alexander Adamchuk (alex(AT)kolmogorov.com), May 05 2007
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