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 A120100 Integers n for which the period of the decimal expansion of 1/n is 6. 1
 7, 13, 14, 21, 26, 28, 35, 39, 42, 52, 56, 63, 65, 70, 77, 78, 84, 91, 104, 105, 112, 117, 126, 130, 140, 143, 154, 156, 168, 175, 182, 189, 195, 208, 210, 224, 231, 234, 252, 259, 260, 273, 280, 286, 297, 308, 312, 315, 325, 336, 350, 351, 364, 378, 385, 390 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The initial terms in the sequence are multiples of either 7 or 13, but the sequence is not exclusively so. a(45) = 297 whose factors include neither 7 nor 13. Next is a(57) = 407 whose factors are 11 and 37. LINKS EXAMPLE a(1) = 7 because 1/7 = 0.142857142857142857+, whose repeating decimal (142857) is 6 digits long. a(57) = 407 because 1/407 = 0.0024570024570024+, whose repeating decimal (002457) is 6 digits long. MATHEMATICA Transpose[Select[Table[{n, Length[RealDigits[1/n][[1, -1]]]}, {n, 500}], #[[2]]==6&]][[1]] (* Harvey P. Dale, Dec 04 2010 *) CROSSREFS Sequence in context: A232437 A275201 A274558 * A308525 A104217 A269163 Adjacent sequences:  A120097 A120098 A120099 * A120101 A120102 A120103 KEYWORD nonn,base AUTHOR Gil Broussard, Aug 15 2006 STATUS approved

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Last modified October 19 21:28 EDT 2019. Contains 328244 sequences. (Running on oeis4.)