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A129781
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The prime(n)-th upper twin prime.
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0
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7, 13, 31, 61, 139, 181, 241, 283, 433, 643, 811, 1033, 1153, 1279, 1429, 1669, 1933, 1999, 2143, 2341, 2551, 2791, 3121, 3361, 3583, 3853, 3931, 4093, 4159, 4261, 5011, 5281, 5641, 5659, 6361, 6553, 6781, 7129, 7351, 7759, 8233, 8389, 9013, 9241, 9433
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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FORMULA
| Prime(n) = the n-th prime number.
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EXAMPLE
| The first prime is 2. The 2nd upper twin prime is 7, which gives the first entry.
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MATHEMATICA
| With[{twprs=Transpose[Select[Partition[Prime[Range[10000]], 2, 1], Last[#]- First[#] == 2&]][[2]]}, Flatten[Table[Take[twprs, {Prime[n]}], {n, 50}]]] (* From Harvey P. Dale, Jul 25 2011 *)
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PROG
| (PARI) g(n) = for(x=1, n, y=twinu(prime(x)); print1(y", ")) twinu(n) = { local(c, x); c=0; x=1; while(c<n, if(isprime(prime(x)+2), c++); x++; ); return(prime(x)) }
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CROSSREFS
| Sequence in context: A060800 A107146 A201601 * A174217 A040061 A091432
Adjacent sequences: A129778 A129779 A129780 * A129782 A129783 A129784
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KEYWORD
| easy,nonn
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AUTHOR
| Cino Hilliard (hillcino368(AT)hotmail.com), May 17 2007
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