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Search: id:A070773
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| A070773 |
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Number of solutions to p(2m)-2p(m)=2n-1, where p(m) = m-th prime. |
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3
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| 1, 1, 1, 1, 1, 1, 1, 3, 1, 2, 2, 0, 1, 0, 2, 1, 1, 3, 1, 1, 0, 1, 2, 0, 2, 1, 1, 1, 3, 2, 1, 3, 0, 1, 2, 2, 0, 0, 0, 0, 2, 1, 0, 3, 0, 3, 2, 3, 3, 1, 0, 0, 2, 2, 3, 2, 0, 3, 1, 0, 1, 1, 0, 1, 1, 1, 1, 7, 1, 2, 2, 1, 1, 1, 1, 2, 1, 0, 2, 0, 0, 2, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 2, 2, 3, 3, 2, 1, 2, 1, 2, 2, 4
(list; graph; listen)
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OFFSET
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1,8
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COMMENT
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p(2m)-2p(m) is approximately 2m Log[2].
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EXAMPLE
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n=12: 2n-1=23, no solution, so a(12)=0; n=8: 2n-1=15, p[2x]={53,61,89},2*p(x)=2*{19,23,37}={38,46,74}, p[2x]-2p[x]={15,15,15}, three solutions, so a(8)=3.
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MATHEMATICA
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j=0; Table[Print[j]; j=0; Do[s=Prime[2*n]-2*Prime[n]; If[Equal[s, 2*k-1], j=j+1], {n, 1, 2*k}], {k, 1, 11000}] (*number of solution=j*)
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CROSSREFS
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Cf. A066066, A022457, A070774, A069890.
Sequence in context: A011086 A103514 A016570 this_sequence A046804 A056529 A087282
Adjacent sequences: A070770 A070771 A070772 this_sequence A070774 A070775 A070776
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), May 06 2002
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