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Search: id:A084701
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| A084701 |
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Smallest k such that k*prime(i)-1 is prime for i = 1 to n. |
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+0
2
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| 2, 2, 4, 6, 120, 120, 120, 21972720, 827779590, 2481129210, 3894254360010
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Perhaps a(10) = 2481129210 (from Prime Curios web page)
For n > 4, a(n) == 0 mod 30. a(10) was reported by a Prime Curios page.
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LINKS
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Chris Caldwell, Prime Curios
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EXAMPLE
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a(4) = 6, 2*6-1 = 11, 3*6-1 = 17, 5*6-1 = 29, 7*6-1 = 41 are all primes.
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MATHEMATICA
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k = 2; Do[ While[ Union[ PrimeQ[ Table[ k*Prime[i] - 1, {i, 1, n}]]] != {True}, k+=2]; Print[k], {n, 1, 8}]
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CROSSREFS
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Cf. A084700.
Sequence in context: A080611 A072707 A086105 this_sequence A113815 A110946 A021449
Adjacent sequences: A084698 A084699 A084700 this_sequence A084702 A084703 A084704
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KEYWORD
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more,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jun 08 2003
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com) and Don Reble (djr(AT)nk.ca), Jun 15 2003
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