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 A126385 #5 Mar 31 2012 12:35:05
%S A126385 1,31,91,269,797,2365,7025,20883,62115,184845,550289,1638775,4881719,
%T A126385 14545715,43350415,129222077,385262397,1148802957,3426077313,
%U A126385 10218944199,30483682935,90944672583,271351287651,809707376697
%N A126385 Number of base 31 n-digit numbers with adjacent digits differing by one or less.
%C A126385 [Empirical] a(base,n)=a(base-1,n)+3^(n-1) for base>=n; a(base,n)=a(base-1,n)+3^(n-1)-2 when base=n-1
%o A126385 (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>1)+($[i+1]`-$[i]`>1))
%K A126385 nonn,base
%O A126385 0,2
%A A126385 _R. H. Hardin_, Dec 26 2006