A235233 Number of (n+1) X (2+1) 0..6 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 6, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).

420, 1288, 3688, 11728, 34916, 113940, 348876, 1158552, 3626376, 12193672, 38853396, 131871756, 426383532, 1457769280, 4770857720, 16406943392, 54238894212, 187427003188, 624847358508, 2167920197880, 7278838832680

Offset

1,1

Comments

Column 2 of A235239.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 6*a(n-1) +47*a(n-2) -331*a(n-3) -846*a(n-4) +7735*a(n-5) +6531*a(n-6) -99876*a(n-7) -4062*a(n-8) +780931*a(n-9) -294777*a(n-10) -3829232*a(n-11) +2187642*a(n-12) +11922251*a(n-13) -7106223*a(n-14) -23840076*a(n-15) +11482195*a(n-16) +31200479*a(n-17) -9197246*a(n-18) -26295345*a(n-19) +2967600*a(n-20) +13895070*a(n-21) +468804*a(n-22) -4403844*a(n-23) -634896*a(n-24) +759672*a(n-25) +171504*a(n-26) -54432*a(n-27) -15552*a(n-28).

Example

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

Crossrefs

Sequence in context: A135196 A259025 A281210 * A251084 A250383 A145678

Adjacent sequences: A235230 A235231 A235232 * A235234 A235235 A235236

Keyword

nonn

Author

R. H. Hardin, Jan 05 2014

Status

approved