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 A043094 #9 Nov 08 2022 17:11:21 %S A043094 0,1,2,3,4,5,6,7,8,10,11,12,13,14,15,16,17,19,20,21,22,23,24,25,26,28, %T A043094 29,30,31,32,33,34,35,37,38,39,40,41,42,43,44,46,47,48,49,50,51,52,53, %U A043094 55,56,57,58,59,60,61,62,65,66,67,68,69,70 %N A043094 Every string of 2 consecutive base 8 digits contains exactly 2 distinct numbers. %t A043094 Select[Range[0,80],FreeQ[Differences[IntegerDigits[#,8]],0]&] (* _Harvey P. Dale_, Nov 08 2022 *) %Y A043094 Cf. A000975 (base-2 analog), A031941 or A043089 (base-3 analog), A031942 or A043090 (base-4 analog), A031943 or A043091 (base-5 analog), A043092, ..., A043096 (base-6 through base-10 analog). %K A043094 nonn,base %O A043094 0,3 %A A043094 _Clark Kimberling_