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 A023805 #14 Mar 22 2025 17:36:57
%S A023805 0,1,2,3,4,5,6,7,8,9,10,11,13,14,15,16,17,18,19,20,21,22,23,25,26,27,
%T A023805 28,29,30,31,32,33,34,35,37,38,39,40,41,42,43,44,45,46,47,49,50,51,52,
%U A023805 53,54,55,56,57,58,59,61,62,63,64,65,66,67,68,69,70,71,73,74
%N A023805 Xenodromes: all digits in base 11 are different.
%C A023805 Considering some base b, there are b numbers with 1 digit, (b-1)*(b-1) numbers with 2 digits -- since leading 0's are not allowed and the second digit must avoid the first. There are (b-1)*(b-1)*(b-2) numbers with 3 digits, (b-1)*(b-1)*(b-2)*..*(b-d+1) numbers with d digits, in total b+(b-1)*sum_{d=2..b} (b-1)!/(b-d)! = b+(b-1)^2* 2F0(1,2-b;;-1) = A001339(b-1). The formula is applicable to sequences A023798 - A023810. This sequence here as A001339(11-1) = 98641011 terms. [From _R. J. Mathar_, Jan 27 2010]
%C A023805 Last term is a(98641011) = 282458553905. - _Charles R Greathouse IV_, Jun 16 2012
%H A023805 Paolo Xausa, <a href="/A023805/b023805.txt">Table of n, a(n) for n = 1..10000</a>
%e A023805 121 (in decimal) = 100 (base 11) is a member of A168186 but not a member of this sequence. - Robert Munafo, Jan 26 2010
%e A023805 156 is in A023805 but not in A168186. - Franklin T. Adams-Watters, Jan 26 2010
%t A023805 Select[Range[0, 100], Max[DigitCount[#, 11]] == 1 &] (* _Paolo Xausa_, Mar 22 2025 *)
%Y A023805 All three of A023805, A160453, A168186 are different.
%K A023805 nonn,base,fini,easy
%O A023805 1,3
%A A023805 _Olivier Gérard_