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 A057303 #17 Feb 23 2016 13:20:32
%S A057303 1,11,12,20,21,23,24,25,26,27,28,29,32,42,52,62,72,82,92,103,111,112,
%T A057303 121,122,123,130,132,134,135,136,137,138,139,143,153,163,173,183,193,
%U A057303 200,202,203,211,212,213,220,221,223,224,225,226,227,228,229,230,231
%N A057303 Numbers n such that the number of distinct digits in n is a digit of n.
%C A057303 The repunits (A000042) are a subsequence. Analogous in construction to the refactorable numbers (A033950).
%D A057303 S. Colton, Unpublished PhD Thesis, University of Edinburgh, 2000.
%H A057303 S. Colton, <a href="http://www.cs.uwaterloo.ca/journals/JIS/colton/joisol.html">Refactorable Numbers - A Machine Invention</a>, J. Integer Sequences, Vol. 2, 1999, #2.
%H A057303 S. Colton, <a href="http://www.dai.ed.ac.uk/homes/simonco/research/hr/">HR - Automatic Theory Formation in Pure Mathematics</a>
%e A057303 103 has 3 distinct digits in base 10 and 3 is a base 10 digit of 103.
%o A057303 (PARI) isok(n) = {my(d = vecsort(digits(n),,8)); vecsearch(d, #d);} \\ _Michel Marcus_, Feb 23 2016
%Y A057303 Cf. A000042.
%K A057303 nonn,base
%O A057303 1,2
%A A057303 Simon Colton (simonco(AT)cs.york.ac.uk), Aug 25 2000