A234915 Number of (n+1) X (2+1) 0..4 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 2, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).

120, 360, 1128, 3912, 13368, 47980, 169128, 615344, 2208840, 8101636, 29440480, 108555776, 397778288, 1471836460, 5423279536, 20112150000, 74378680256, 276229599252, 1023983273704, 3806366759376, 14131890787656, 52561443989340

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +20*a(n-2) -60*a(n-3) -110*a(n-4) +376*a(n-5) +70*a(n-6) -758*a(n-7) +309*a(n-8) +455*a(n-9) -336*a(n-10) -16*a(n-11) +60*a(n-12) -12*a(n-13).

Example

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

Crossrefs

Column 2 of A234921.

Sequence in context: A144524 A052768 A242845 * A061218 A321841 A052778

Adjacent sequences: A234912 A234913 A234914 * A234916 A234917 A234918

Keyword

nonn

Author

R. H. Hardin, Jan 01 2014

Status

approved