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 A125538 #6 Mar 31 2012 12:35:05 %S A125538 1,7,2067,26587217,14749946711237,353372896021348132827, %T A125538 365544303118982657966348922687, %U A125538 16327402400665015344535793527620336180117 %N A125538 Number of n X n arrays with entries in 1..7 in which adjacent entries differ by 5 or less (adjacent means in x or y directions). %C A125538 [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 A125538 (S/R) stvar $[N][N]:(0.. M-1) init $[][]:=0 asgn $[][]->{*} kill +[i in 0.. N-2](+[j in 0.. N-1](($[i][j]`-$[i+1][j]`>5)+($[i+1][j]`-$[i][j]`>5)+($[j][i]`-$[j][i+1]`>5)+($[j][i+1]`-$[j][i]`>5))) %K A125538 nonn %O A125538 0,2 %A A125538 _R. H. Hardin_, Dec 31 2006