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Search: id:A054904
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| A054904 |
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x=a(n) is the smallest composite number such that Sigma[x+6n]=Sigma[x]+6n, where Sigma = A000203. |
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+0
6
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| 104, 65, 20, 80, 44, 125, 45, 63, 40, 99, 56, 70, 296, 125, 88, 110, 104, 145, 212, 182, 80, 170, 333, 105, 369, 185, 184, 135, 180, 301, 356, 185, 1859, 329, 176, 195, 4916, 434, 612, 287, 140, 185, 776, 255, 524, 413, 344, 205, 272, 329, 567, 215, 320, 469
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OFFSET
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1,1
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COMMENT
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If Sigma[x+d]=Sigma[x]+d and d=6k, then composite solutions seem to be more frequent and arise sooner.
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FORMULA
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Sigma[x+6n]=Sigma[x]+6n, a(n)=Min[x] and it is composite.
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EXAMPLE
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n=20, 6n=120, a(n)=182, Sigma[182]+120=336+120=456=Sigma[182+120]=Sigma[202]
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CROSSREFS
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Cf. A015914-A015917, A023200-A023203, A054799, A054903-A054905.
Sequence in context: A106297 A090849 A091025 this_sequence A117845 A163554 A045208
Adjacent sequences: A054901 A054902 A054903 this_sequence A054905 A054906 A054907
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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 23 2000
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