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Search: id:A098438
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| A098438 |
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Numbers n such that (30^n-1)/29 is prime. |
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+0
13
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OFFSET
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1,1
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COMMENT
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Next term after 8447 is greater than 10000. - Ryan Propper (rpropper(AT)stanford.edu), Jun 25 2005
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REFERENCES
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H. Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930.
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LINKS
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H. Lifchitz, Mersenne and Fermat primes field
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MATHEMATICA
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Do[If[PrimeQ[(30^n - 1)/29], Print[n]], {n, 1, 10000}] (Propper)
Select[Prime[Range[100]], PrimeQ[(30^#-1)/29]&] - Alexander Adamchuk (alex(AT)kolmogorov.com), Feb 11 2007
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PROGRAM
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(MAGMA) for i in [1..500] do if i mod 50 eq 0 then print "counter equals", counter; end if; if IsPrime(i) then n := 0; for j in [0..i-1] do n +:= 30^j; end for; if IsPrime(n) then print n; print i; end if; end if; end for;
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CROSSREFS
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Cf. A028491, A004061, A004062, A004063, A004023, A005808, A004064, A016054, A006032, A006033, A006034, A006035.
Cf. A127995, A127996, A127997, A127998, A127999, A128000, A128002, A128003, A128004, A128005.
Searching in the OEIS for 'repunit' gives many similar sequences.
Adjacent sequences: A098435 A098436 A098437 this_sequence A098439 A098440 A098441
Sequence in context: A078790 A069506 A123165 this_sequence A064772 A107989 A069504
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KEYWORD
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easy,nonn,more
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AUTHOR
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Tim Honeywill, Jon Ingram and Paul Boddington (tch(AT)maths.warwick.ac.uk), Oct 26 2004
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EXTENSIONS
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a(7) - a(10), corresponding to pseudoprimes, from Ryan Propper (rpropper(AT)stanford.edu), Jun 25 2005
a(10) = 8447 was found by Richard Fischer in 2004. - Alexander Adamchuk (alex(AT)kolmogorov.com), Feb 11 2007
Edited by njas Jan 25 2008 at the suggestion of Herman Jamke (hermanjamke(AT)fastmail.fm)
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