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 A125532 Number of n X n arrays with entries in 1..4 in which adjacent entries differ by 2 or less (adjacent means in x or y directions). 0

%I

%S 1,4,162,75398,386994338,22039625597766,13914188992963436802,

%T 97391265572623379728784646,7557580190940015054807296049439074,

%U 6502004785230840000033839573162175747164038

%N Number of n X n arrays with entries in 1..4 in which adjacent entries differ by 2 or less (adjacent means in x or y directions).

%C [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 (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 nonn

%O 0,2

%A _R. H. Hardin_, Dec 31 2006

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Last modified January 27 16:20 EST 2022. Contains 350608 sequences. (Running on oeis4.)