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Search: id:A114263
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| A114263 |
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n(k) is the minimum number that makes Prime[k]+2*Prime[k+n] a prime. |
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+0
3
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| 1, 1, 1, 1, 1, 4, 5, 3, 2, 2, 3, 1, 1, 4, 5, 1, 5, 4, 2, 2, 2, 2, 1, 3, 1, 1, 8, 4, 1, 1, 2, 3, 9, 2, 5, 2, 2, 9, 6, 1, 1, 1, 1, 2, 3, 4, 1, 4, 5, 8, 11, 1, 11, 4, 5, 1, 4, 1, 5, 8, 1, 1, 1, 1, 2, 5, 1, 5, 9, 2, 1, 10, 3, 4, 4, 5, 5, 6, 7, 4, 1, 1, 2, 4, 13, 6, 6, 6, 7, 9, 1, 3, 1, 7, 3, 9, 1, 3, 3, 6, 3, 8, 2
(list; graph; listen)
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OFFSET
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2,6
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EXAMPLE
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k=2: Prime[2]+2*Prime[2+1]=3+2*5=13 is prime, so n(2)=1;
k=3: Prime[3]+2*Prime[3+1]=5+2*7=19 is prime, so n(2)=1;
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k=7: Prime[7]+2*Prime[7+1]=17+2*19=55 is not prime
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Prime[7]+2*Prime[7+4]=17+2*31=79 is prime, so n(7)=4;
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MATHEMATICA
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Table[p1 = Prime[n1]; n2 = 1; p2 = Prime[n1 + n2]; While[cp = p1 + 2* p2; ! PrimeQ[cp], n2++; p2 = Prime[n1 + n2]]; n2, {n1, 2, 201}]
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CROSSREFS
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Cf. A114227, A114230, A073703, A114235, A114262, A114228, A114231, A114233, A114236.
Sequence in context: A019743 A010663 A016494 this_sequence A094850 A124118 A016716
Adjacent sequences: A114260 A114261 A114262 this_sequence A114264 A114265 A114266
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KEYWORD
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easy,nonn
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AUTHOR
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Lei Zhou (lzhou5(AT)emory.edu), Nov 20 2005
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