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Search: id:A114266
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| A114266 |
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n(k) is the minimum number that makes 2*Prime[k]+Prime[k+n] a prime. |
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+0
2
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| 1, 1, 1, 3, 3, 1, 1, 1, 3, 1, 2, 4, 6, 2, 6, 2, 1, 2, 5, 5, 2, 1, 2, 3, 5, 3, 1, 6, 1, 1, 8, 2, 4, 7, 1, 9, 3, 2, 9, 7, 5, 10, 4, 5, 1, 5, 5, 1, 1, 1, 8, 1, 1, 4, 6, 2, 1, 2, 12, 10, 1, 11, 8, 3, 11, 2, 2, 1, 4, 1, 7, 2, 3, 2, 11, 2, 3, 3, 3, 1, 1, 5, 2, 5, 1, 7, 3, 3, 4, 6, 4, 7, 4, 1, 9, 5, 3, 2, 4, 7, 2, 9, 2
(list; graph; listen)
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OFFSET
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1,4
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EXAMPLE
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k=1: 2*Prime[1]+Prime[1+1]=2*2+3=7 is prime, so n(1)=1;
k=2: 2*Prime[2]+Prime[2+1]=2*3+5=11 is prime, so n(2)=1;
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k=4: 2*Prime[4]+Prime[4+1]=2*7+11=25 is not prime
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2*Prime[4]+Prime[4+3]=2*7+17=31 is prime, so n(4)=3;
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MATHEMATICA
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Table[p1 = Prime[n1]; n2 = 1; p2 = Prime[n1 + n2]; While[cp = 2*p1 + p2; ! PrimeQ[cp], n2++; p2 = Prime[n1 + n2]]; n2, {n1, 1, 200}]
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CROSSREFS
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Cf. A114227, A114230, A073703, A114235, A114262, A114228, A114231, A114233, A114236, A114263, A114265.
Sequence in context: A079075 A086703 A072917 this_sequence A135910 A107333 A098505
Adjacent sequences: A114263 A114264 A114265 this_sequence A114267 A114268 A114269
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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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