cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A382498 Smallest k such that the fractional part of 1/k is pandigital in base n.

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%I A382498 #18 Mar 30 2025 12:49:10
%S A382498 3,5,13,7,11,11,11,43,17,13,17,19,17,19,79,23,29,23,23,23,31,47,31,73,
%T A382498 29,29,41,41,41,47,37,43,41,37,137,59,47,47,47,47,59,47,47,47,67,59,
%U A382498 53,241,53,53,59,71,59,59,59,67,73,61,73,67,71,67,383,71,79
%N A382498 Smallest k such that the fractional part of 1/k is pandigital in base n.
%C A382498 It appears that for squarefree n, a(n) has a reptend of maximal length and for square n, a(n) has a reptend of half the maximal length.
%C A382498 Not every prime appears in this sequence - excluding 2, the first missing prime is 109.
%C A382498 The first composite term is a(81).
%C A382498 How many times can a term appear consecutively?
%C A382498 How does a(n) grow with n?
%H A382498 SeqFans Mailing List, <a href="https://groups.google.com/g/seqfan/c/xr_5QtYnM4E">Smallest pandigital reptend of 1/n in base b</a>
%e A382498 a(10) = 17 because 1/17 = 0.(0588235294117647)... in base 10 where the brackets indicate the reptend. Every digit 0-9 appears within the reptend and is the smallest unit fraction where this is the case.
%e A382498 a(36) = 137 because 1/137 = 0.(09gjyy5s47cvj6khv9q0ix3xwbk8epr2d4zqjg11u7vsn4gtfi4q9zh2w23ofrla8xmv)... in base 36 where the digits 0-9 and letters a-z have been used as additional digits. Every character appears at least once.
%Y A382498 Cf. A001913, A261773.
%K A382498 nonn,base
%O A382498 2,1
%A A382498 _Joshua Searle_, Mar 29 2025