A125540 Number of n X n arrays with entries in 1..8 in which adjacent entries differ by 6 or less (adjacent means in x or y directions).

1, 8, 3650, 97167566, 149893105802018, 13409953777346510733710, 69569862634707662759990393452322, 20929881875746750076174309956907291103359630

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]`-$[i+1][j]`>6)+($[i+1][j]`-$[i][j]`>6)+($[j][i]`-$[j][i+1]`>6)+($[j][i+1]`-$[j][i]`>6)))

Crossrefs

Sequence in context: A318067 A295170 A087925 * A221109 A221243 A351409

Adjacent sequences: A125537 A125538 A125539 * A125541 A125542 A125543

Keyword

nonn

Author

R. H. Hardin, Dec 31 2006

Status

approved