A125539 Number of n X n arrays with entries in 1..8 in which adjacent entries differ by 5 or less (adjacent means in x or y directions).

1, 8, 2902, 52127130, 45120225704486, 1888405717902201691046, 3819825084723229625771326323002, 373453238394596300163358238712837771590526

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..7.

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]`-$[i+1][j]`>5)+($[i+1][j]`-$[i][j]`>5)+($[j][i]`-$[j][i+1]`>5)+($[j][i+1]`-$[j][i]`>5)))

Crossrefs

Sequence in context: A185901 A078525 A280282 * A297922 A298546 A298336

Adjacent sequences: A125536 A125537 A125538 * A125540 A125541 A125542

Keyword

nonn

Author

R. H. Hardin, Dec 31 2006

Status

approved