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A114227
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Smallest odd prime q that makes the n-th prime p[n] plus 2*q (p[n]+2q) a prime.
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16
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3, 3, 3, 3, 3, 5, 3, 7, 3, 3, 3, 5, 3, 3, 7, 3, 3, 13, 3, 5, 3, 7, 3, 3, 3, 3, 11, 7, 5, 3, 7, 5, 7, 3, 3, 5, 3, 3, 7, 5, 3, 3, 7, 17, 11, 3, 3, 5, 3, 19, 5, 3, 3, 3, 7, 3, 3, 13, 5, 7, 3, 3, 17, 7, 3, 5, 3, 5, 3, 7, 3, 3, 5, 3, 37, 11, 19, 5, 7, 5, 13, 3, 5, 3, 7, 3, 3, 23, 37, 31, 11, 43, 5, 3, 7, 13, 17
(list; graph; refs; listen; history; internal format)
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OFFSET
| 3,1
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EXAMPLE
| p[3]=5, 5+2*3=11 is prime, so q[3]=3;
p[4]=7, 7+2*3=13 is prime, so q[4]=3;
...
p[20]=71, 71+2*13=97 is prime, so q[20]=13
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MATHEMATICA
| Table[p1 = Prime[n1]; n2 = 2; p2 = 3; While[ cp = p1 + 2*p2; ! PrimeQ[cp], n2++; p2 = Prime[n2]]; p2, {n1, 3, 202}]
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CROSSREFS
| Sequence in context: A176873 A050499 A147752 * A187469 A112593 A204854
Adjacent sequences: A114224 A114225 A114226 * A114228 A114229 A114230
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KEYWORD
| easy,nonn
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AUTHOR
| Lei Zhou (lzhou5(AT)emory.edu), Nov 18 2005
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