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A174393
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Numbers k such that 6*prime(k) -+ {1,5} are all prime.
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0
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1, 2, 4, 7, 106, 388, 930, 2999, 3127, 3974, 4982, 5154, 6350, 6612, 6750, 7661, 7693, 8783, 10156, 10465, 11989, 13101, 13266, 15349, 15351, 17476, 18087, 19305, 20670, 21434, 22671, 23134, 23613, 23667, 24493, 24509, 25780, 27474, 28764, 30457
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listen;
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internal format)
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OFFSET
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1,2
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LINKS
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EXAMPLE
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a(1)=1 because
prime(1)*6 - 5 = 7,
prime(1)*6 - 1 = 11,
prime(1)*6 + 1 = 13, and
prime(1)*6 + 5 = 17
are all prime.
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MAPLE
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isA174393 := proc(n) local p ; p := ithprime(n) ; isprime(p*6-1) and isprime(p*6-5) and isprime(p*6+1) and isprime(p*6+5); end proc: for n from 1 to 40000 do if isA174393(n) then printf("%d, ", n) ; end if; end do: # R. J. Mathar, Mar 29 2010
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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