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 A023810 #12 Aug 11 2021 18:16:28 %S A023810 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,18,19,20,21,22,23,24,25,26, %T A023810 27,28,29,30,31,32,33,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50, %U A023810 52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,69,70,71,72 %N A023810 Xenodromes: all digits in base 16 are different. %C A023810 Last term is a(53319412081141) = 18364758544493064720 = 'fedcba9876543210'. - _Charles R Greathouse IV_, Jun 16 2012 %t A023810 Select[Range[0,80],Max[DigitCount[#,16]]<2&] (* _Harvey P. Dale_, Aug 11 2021 *) %K A023810 nonn,base,fini,easy %O A023810 1,3 %A A023810 _Olivier Gérard_