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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).
0
1, 5, 247, 156579, 1191861707, 109495018399901, 121266251495154433997, 1619036215215662119089701145, 260573722827793207854814217971985907
OFFSET
0,2
COMMENTS
[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)).
PROG
(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)))
CROSSREFS
Sequence in context: A215910 A097323 A166943 * A068727 A135095 A219872
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 31 2006
STATUS
approved