A235270 Number of (n+1) X (n+1) 0..4 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 5 (constant-stress 1 X 1 tilings).

40, 208, 632, 2344, 6232, 20440, 51800, 160888, 401560, 1215928, 3032792, 9077944, 22776472, 67860280

Offset

1,1

Comments

Diagonal of A235280.

Links

Table of n, a(n) for n=1..14.

Formula

Empirical: a(n) = a(n-1) +23*a(n-2) -23*a(n-3) -200*a(n-4) +200*a(n-5) +820*a(n-6) -820*a(n-7) -1584*a(n-8) +1584*a(n-9) +1152*a(n-10) -1152*a(n-11) [see A235280 for an assumption].

Example

Some solutions for n=4:
  4 1 4 2 4     4 1 3 1 4     2 4 1 4 1     0 3 0 2 0
  0 2 0 3 0     1 3 0 3 1     4 1 3 1 3     3 1 3 0 3
  4 1 4 2 4     4 1 3 1 4     2 4 1 4 1     0 3 0 2 0
  1 3 1 4 1     1 3 0 3 1     3 0 2 0 2     4 2 4 1 4
  4 1 4 2 4     3 0 2 0 3     2 4 1 4 1     0 3 0 2 0

Crossrefs

Sequence in context: A187379 A077818 A247405 * A181637 A111176 A072108

Adjacent sequences: A235267 A235268 A235269 * A235271 A235272 A235273

Keyword

nonn

Author

R. H. Hardin, Jan 05 2014

Status

approved