OFFSET
1,2
COMMENTS
This sequence differs from A052039 in how it treats reciprocals with terminating representation, i.e., the values 1/k for integers k whose prime factors are 2 and/or 5. For example, here we assume 1/5 = 0.2000... which leads to a(20) = 5, while in A052039 we consider 1/5 = 0.2 (without trailing zeros), which leads to A052039(20) = 48 instead.
EXAMPLE
a(123) = 81 because 1/81 = 0.0(123)4... and 81 is the smallest number with this property.
MATHEMATICA
a[n_] := Block[{d = IntegerDigits[n], m, k = 1}, m = Length[d]; While[ RealDigits[1/k, 10, m][[1]] != d, k++]; k]; Array[a, 65]
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Giovanni Resta, Oct 20 2019
STATUS
approved