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).

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)).

Links

Table of n, a(n) for n=0..8.

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

Adjacent sequences: A125530 A125531 A125532 * A125534 A125535 A125536

Keyword

nonn

Author

R. H. Hardin, Dec 31 2006

Status

approved