A234720 Number of (n+1) X (n+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 7 (constant-stress 1 X 1 tilings).

240, 3976, 33560, 357208, 2557656, 23137720, 157274648, 1310504248, 8760624600

Offset

1,1

Links

Table of n, a(n) for n=1..9.

Example

Some solutions for n=3:
  1 6 3 7     4 0 6 0     2 5 0 3     5 1 7 2     0 5 3 3
  3 1 5 2     1 4 3 4     6 2 4 0     1 4 3 5     4 2 7 0
  0 5 2 6     5 1 7 1     4 7 2 5     5 1 7 2     1 6 4 4
  2 0 4 1     1 4 3 4     7 3 5 1     2 5 4 6     4 2 7 0

Crossrefs

Diagonal of A234728.

Sequence in context: A005950 A279746 A004536 * A249533 A324070 A145094

Adjacent sequences: A234717 A234718 A234719 * A234721 A234722 A234723

Keyword

nonn

Author

R. H. Hardin, Dec 30 2013

Status

approved