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A125537

Number of n X n arrays with entries in 1..7 in which adjacent entries differ by 4 or less (adjacent means in x or y directions).

1, 7, 1527, 11721313, 3050388738539, 27037458180935427547, 8157016618633297682357104957, 83768469285967811192253950787571671419, 29282610870399702055320868574328652947738735891523

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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]`-$[i+1][j]`>4)+($[i+1][j]`-$[i][j]`>4)+($[j][i]`-$[j][i+1]`>4)+($[j][i+1]`-$[j][i]`>4)))

CROSSREFS

Sequence in context: A362060 A265963 A191957 * A264742 A308441 A220989

Adjacent sequences: A125534 A125535 A125536 * A125538 A125539 A125540

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 31 2006

STATUS

approved

URL: https://oeis.org/A125537

⇱ A125537 - OEIS