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Search: id:A081318
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| A081318 |
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Largest factor of 10^a(n)-1 does not produce a decimal fraction period of length n. |
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+0
2
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| 6, 18, 22, 30, 32, 38, 42, 46, 54, 66, 74, 78, 82, 90, 94, 96, 110, 118, 132, 138, 146, 154, 162, 174, 186, 194, 198, 206, 210, 218
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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A061075(a(n)) is not equal to A005422(a(n))
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EXAMPLE
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30 is in the sequence because the factorization of 10^30-1 is 3^3*7*11*13*31*37*41*211*241*271*_2161_*9091*2906161 2906161 occurs already in 10^15-1=3^3*31*37*41*271*2906161 producing a fraction period of 15, (1/2906161=0.000000344096559000000344096559000000344...) 9091 occurs in 10^10-1=3^2*11*41*271*9091 producing a fraction period of 10. (1/9091=0.0001099989000109998900010999...) 2161 gives the full fraction period 30: 1/2161=0.00462748727440999537251272559000462748727440999537251272559000...
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CROSSREFS
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Cf. A081317.
Sequence in context: A077663 A025163 A022418 this_sequence A011775 A015707 A101527
Adjacent sequences: A081315 A081316 A081317 this_sequence A081319 A081320 A081321
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KEYWORD
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more,nonn
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AUTHOR
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Hugo Pfoertner (hugo(AT)pfoertner.org), Mar 18 2003
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EXTENSIONS
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More terms from Hans Havermann (pxp(AT)rogers.com), May 31 2003
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