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A118071
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Primes which are sum of twin prime pair + 1.
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2
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13, 37, 61, 277, 397, 457, 541, 1201, 1237, 1321, 1621, 1657, 2557, 2857, 3217, 4057, 4177, 4261, 4621, 5101, 5581, 6337, 6661, 6781, 7057, 7537, 8101, 8317, 8461, 8521, 8677, 9277, 9601, 10837, 10957, 11317, 11701, 12541, 12601, 12721, 13381, 13921
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Subset of A092738 - Paolo P. Lava (paoloplava(AT)gmail.com), Dec 21 2007
Primes of the form 2*greather of twin primes-1. [From Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Apr 26 2010]
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FORMULA
| {A001359(k) + A006512(k) + 1} INTERSECT {A000040}. {A054735(k) + 1} INTERSECT {A000040}. {2*A001359(k) + 3} INTERSECT {A000040}.
a(n)=2*A006512(n)-1. [From Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Apr 26 2010]
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EXAMPLE
| a(1) = 13 = 5 + 7 + 1 where (5,7) is a twin prime pair.
a(2) = 37 = 17 + 19 + 1.
a(3) = 61 = 29 + 31 + 1.
a(4) = 277 = 137 + 139 + 1.
a(5) = 397 = 197 + 199 + 1.
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MAPLE
| P:=proc(n) local a, i; for i from 1 by 1 to n do if ithprime(i+1)-ithprime(i)=2 then a:=ithprime(i+1)+ithprime(i)+1; if isprime(a) then print(a); fi; fi; od; end: P(300); - Paolo P. Lava (paoloplava(AT)gmail.com), Dec 21 2007
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MATHEMATICA
| lst={}; d=2; Do[p1=Prime[n]; p2=Prime[n+1]; p=p1+p2+1; If[PrimeQ[p]&&p2-p1==d, AppendTo[lst, p]], {n, 10^3}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Aug 14 2008]
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CROSSREFS
| Cf. A000040, A001359, A006512, A054735.
Sequence in context: A034938 A139530 A138368 * A147207 A146877 A049742
Adjacent sequences: A118068 A118069 A118070 * A118072 A118073 A118074
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KEYWORD
| easy,nonn
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AUTHOR
| Jonathan Vos Post (jvospost3(AT)gmail.com), May 11 2006
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EXTENSIONS
| Added more terms Vladimir Orlovsky (4vladimir(AT)gmail.com), Mar 10 2009
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