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A098438
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Numbers k such that (30^k - 1)/29 is prime.
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10
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OFFSET
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1,1
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COMMENTS
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LINKS
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MATHEMATICA
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Do[If[PrimeQ[(30^n - 1)/29], Print[n]], {n, 1, 10000}] (* Ryan Propper, Jun 25 2005 *)
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PROG
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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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Searching in the OEIS for 'repunit' gives many similar sequences.
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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a(5)-a(7), corresponding to probable primes, from Ryan Propper, Jun 25 2005
Edited by N. J. A. Sloane Jan 25 2008 at the suggestion of Herman Jamke (hermanjamke(AT)fastmail.fm)
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STATUS
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approved
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