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.
%I A288941 #7 Jun 20 2017 23:29:03 %S A288941 123456789,203456789,103456789,102456789,102356789,102346789, %T A288941 102345789,102345689,102345679,102345678,23456789,203456798,30456789, %U A288941 20456789,20356789,20346789,20345789,20345689,20345679,20345678,13456789 %N A288941 a(n) is the least natural number not included earlier having all decimal digits except the digits in n; if n is pandigital or zeroless pandigital, a(n) is simply the least natural number not included earlier. %C A288941 A rearrangement of the natural numbers by definition as there are an infinite number of pandigital numbers (A171102) and zeroless pandigital numbers (A050289). %C A288941 Leading zeros are not permitted. The "zeroless pandigital" criterion is used also because there is just one number with the digit 0 only and we wish all terms to be distinct. %C A288941 What values are a(A050289(1)) = a(123456789) and a(A171102(1)) = a(1023456789)? %H A288941 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %e A288941 For n = 0, a(0) = 123456789, the least natural number containing all decimal digits but the digit 0. %e A288941 For n = 11, a(11) = 203456798, which has all decimal digits but the digit 1 and is the first such number with that property that is larger than 203456789 (= a(1)). %Y A288941 Cf. A050289, A171102. %K A288941 nonn,base %O A288941 0,1 %A A288941 _Rick L. Shepherd_, Jun 19 2017