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 A125533 #8 May 31 2023 15:42:11
%S A125533 1,5,247,156579,1191861707,109495018399901,121266251495154433997,
%T A125533 1619036215215662119089701145,260573722827793207854814217971985907
%N A125533 Number of n X n arrays with entries in 1..5 in which adjacent entries differ by 2 or less (adjacent means in x or y directions).
%C A125533 [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 A125533 (S/R) stvar $[N][N]:(0.. M-1) init $[][]:=0 asgn $[][]->{*} kill +[i in 0.. N-2](+[j in 0.. N-1](($[i][j]`-$[i+1][j]`>2)+($[i+1][j]`-$[i][j]`>2)+($[j][i]`-$[j][i+1]`>2)+($[j][i+1]`-$[j][i]`>2)))
%K A125533 nonn
%O A125533 0,2
%A A125533 _R. H. Hardin_, Dec 31 2006