A345467 Ratios R(k)/k for which R(k) / k is an integer, where R(k) = A002275(k) is a repunit.
1, 37, 12345679, 4115226337448559670781893, 1371742112482853223593964334705075445816186556927297668038408779149519890260631
Offset: 1
Examples
For n = 2, a(2) = 111/3 = 37. For n = 3, a(3) = 111111111/9 = 12345679.
Programs
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Mathematica
s = Join[{1}, Select[Range[3, 81, 6], PowerMod[10, #, #] == 1 &]]; Table[(10^n - 1)/(9*n), {n, s}] (* Amiram Eldar, Jun 20 2021 *) -
Python
[(10**n-1)//(9*n) for n in range(1, 300) if not (10**n-1)//9 % n]
Comments