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Search: id:A100424
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| A100424 |
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A sieve transform applied three times to the positive integers. |
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+0
5
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| 2, 3, 13, 37, 107, 139, 223, 251, 359, 397, 503, 647, 683, 857, 887, 1033, 1151, 1249, 1291, 1429, 1493, 1601, 1667, 1783, 1831, 2003, 2053, 2267, 2377, 2459, 2593, 2677, 2753, 2801, 2903, 3119, 3209, 3347, 3461, 3557, 3607, 3727, 3851, 4079, 4139, 4243
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The process is described in A099361. The first application of the sieve transform produces the prime numbers A000040. The second application yields sequence A099361. In principle, the sieve transform can be applied to any sequence of positive integers. For instance, the sieve transform of the positive even numbers is 2, 4, 8, 16,.... Also note that the transform can produce a finite sequence. See A100425 and A100426 for more examples.
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..1000
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MATHEMATICA
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SieveTransform[b_List] := Module[{d, nn=Length[b], a=b}, Do[d=a[[i]]; If[d>1, Do[a[[j]]=-1, {j, i+d, nn, d}]], {i, nn}]; DeleteCases[a, -1]]; SieveTransform[SieveTransform[SieveTransform[Range[2, 5000]]]]
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CROSSREFS
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Cf. A099361, A100425, A100426.
Sequence in context: A107387 A151461 A082539 this_sequence A141511 A117528 A122719
Adjacent sequences: A100421 A100422 A100423 this_sequence A100425 A100426 A100427
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KEYWORD
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nonn
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AUTHOR
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T. D. Noe (noe(AT)sspectra.com), Nov 19 2004
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