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A069179
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Least number X such that for each k in (0 to n-1), 2^k*X-1 and 2^k*X+1 are primes. That is, there are N twin primes, each the "double" of the previous.
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1
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OFFSET
| 1,1
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COMMENTS
| a(6)=73768891456260 might be called a(6.5), since 64*a(6)+1 is prime. But 64*a(6)-1 is 167*1021*44533*621769, alas.
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EXAMPLE
| a(3) = 211050 because 1*a(3)-1, 1*a(3)+1, 2*a(3)-1, 2*a(3)+1, 4*a(3)-1 and 4*a(3)+1 are all prime.
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CROSSREFS
| Equals A068635 + 1.
Sequence in context: A077305 A146294 A133982 * A058377 A023961 A147863
Adjacent sequences: A069176 A069177 A069178 * A069180 A069181 A069182
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KEYWORD
| nonn
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AUTHOR
| Don Reble (djr(AT)nk.ca), Apr 09 2002
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