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Search: id:A090795
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| A090795 |
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a(n) = lesser of a pair of twin primes p, q=p+2 such that product of first n primes plus p is a prime and also product of first n primes plus q is a prime. |
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+0
1
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| 3, 5, 11, 17, 29, 59, 41, 41, 641, 101, 419, 101, 269, 179, 107, 827, 1319, 311, 1949, 1667, 1619, 1787, 2267, 4931, 4241, 1619, 461, 809, 12107, 191, 1301, 1721, 13679, 4217, 3527, 11717, 11351, 17789, 23057, 17489, 65579, 22271, 16451, 6299, 1019
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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a(3)=11 because prime(3)=5, primorial(5)=5*3*2=30, 11 and 13 are twin primes and 30+11 = 41 and 43 are also twin primes.
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MATHEMATICA
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Do[p = Fold[ Times, 1, Prime[ Range[n]]]; k = 2; While[q = Prime[k]; !PrimeQ[q + 2] || !PrimeQ[p + q] || !PrimeQ[p + q + 2], k++ ]; Print[q], {n, 1, 45}] (from Robert G. Wilson v)
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CROSSREFS
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Cf. primorials A002110, twin primes A001359.
Sequence in context: A147015 A147023 A108402 this_sequence A087732 A108542 A006450
Adjacent sequences: A090792 A090793 A090794 this_sequence A090796 A090797 A090798
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KEYWORD
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easy,nonn
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AUTHOR
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Donald S. McDonald (don.mcdonald(AT)paradise.net.nz), Feb 10 2004
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EXTENSIONS
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More terms from Ray Chandler (rayjchandler(AT)sbcglobal.net) and Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 10 2004
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