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 A023809 #10 Oct 10 2012 15:40:39 %S A023809 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,17,18,19,20,21,22,23,24,25,26, %T A023809 27,28,29,30,31,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,49,50,51, %U A023809 52,53,54,55,56,57,58,59,60,61,62,63,65,66,67,68,69,70,71,72 %N A023809 Xenodromes: all digits in base 15 are different. %C A023809 Last term is a(3317652307271) = 435659737878916215. - _Charles R Greathouse IV_, Jun 16 2012 %t A023809 Select[Range[0,100],Max[DigitCount[#,15]]==1&] (* _Harvey P. Dale_, Oct 10 2012 *) %K A023809 nonn,base,fini,easy %O A023809 1,3 %A A023809 _Olivier Gérard_