A217646 Periods associated with A217611.
2, 1, 6, 3, 18, 9, 30, 42, 78, 114, 138, 87, 330, 318, 189, 462, 408, 504, 303, 561, 1002, 2040, 1794, 1746, 2418, 2790, 1389, 3894, 4722, 6738, 4077, 14610, 14616, 15294, 16662, 18966, 10641, 27144, 26142, 39360, 31638
Offset: 1
Examples
The octal expansion of 1/73 is 0.007007..., having a period of 3 and it is the only prime with that period.
Crossrefs
Cf. A217611.
Programs
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Mathematica
lst1 = {}; lst2 = {}; lst4 = {}; Do[c = Cyclotomic[n, 8]; q = c/GCD[n, c]; If[PrimePowerQ[q], p = FactorInteger[q][[1, 1]]; AppendTo[lst1, p]; AppendTo[lst2, n]], {n, 561}]; lst3 = Sort[lst1]; Do[AppendTo[lst4, Take[lst2, Flatten@Position[lst1, lst3[[p]]]]], {p, Length@lst3}]; Flatten[lst4]