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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
 1, 4, 162, 75398, 386994338, 22039625597766, 13914188992963436802, 97391265572623379728784646, 7557580190940015054807296049439074, 6502004785230840000033839573162175747164038 (list; graph; refs; listen; history; text; internal format)
 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)) LINKS 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: A041779 A222394 A306350 * A229405 A211157 A185857 Adjacent sequences:  A125529 A125530 A125531 * A125533 A125534 A125535 KEYWORD nonn AUTHOR R. H. Hardin, Dec 31 2006 STATUS approved

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Last modified August 8 14:35 EDT 2020. Contains 336298 sequences. (Running on oeis4.)