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 A125541 #6 Mar 31 2012 12:35:05
%S A125541 1,9,4999,183051647,432993880473035,66327998573151304476953,
%T A125541 657786158098403835519781868703261,
%U A125541 422337116619421509499034109697459735541947069
%N A125541 Number of n X n arrays with entries in 1..9 in which adjacent entries differ by 6 or less (adjacent means in x or y directions).
%C A125541 [Empirical] a(base+1,n,diff)=a(base,n,diff)+F(n,diff) for base>=2.diff.(n-1) and F(n,diff)= (n=2, A063496(diff+1)) (n=3, A068744(diff+1)) (n=4, A068745(diff+1)) (n=5, A068746(diff+1)) (n=6, A068747(diff+1))
%o A125541 (S/R) stvar $[N][N]:(0.. M-1) init $[][]:=0 asgn $[][]->{*} kill +[i in 0.. N-2](+[j in 0.. N-1](($[i][j]`-$[i+1][j]`>6)+($[i+1][j]`-$[i][j]`>6)+($[j][i]`-$[j][i+1]`>6)+($[j][i+1]`-$[j][i]`>6)))
%K A125541 nonn
%O A125541 0,2
%A A125541 _R. H. Hardin_, Dec 31 2006