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 A039667 #17 Aug 11 2024 14:41:31
%S A039667 192,219,273,327
%N A039667 Numbers k that together with their double and triple contain every digit from 1-9 exactly once.
%D A039667 D. Wells, Curious and interesting numbers, Penguin Books, p. 128.
%H A039667 P. De Geest, <a href="https://www.worldofnumbers.com/ninedigits.htm">Nine digits digressions</a>
%e A039667 k=327 -> 2k=654 -> 3k=981 and 327654981 is a 'nine-digit' number.
%t A039667 pdnQ[n_]:=Sort[Flatten[IntegerDigits[{n,2n,3n}]]]==Range[9]; Select[Range[987],pdnQ] (* _Harvey P. Dale_, Jul 07 2012 *)
%Y A039667 Cf. A050289.
%K A039667 nonn,base,fini,full
%O A039667 0,1
%A A039667 _Felice Russo_
%E A039667 Corrected by _Patrick De Geest_, Mar 15 2000
%E A039667 Better definition from _Tanya Khovanova_, Mar 08 2021