A251050 Number of (n+1) X (3+1) 0..3 arrays with no 2 X 2 subblock having the sum of its diagonal elements greater than the absolute difference of its antidiagonal elements.

854, 4334, 10289, 24893, 53306, 114512, 237143, 498593, 1050871, 2263156, 4941211, 10973705, 24635963, 55831811, 127245743, 291219638, 668084936, 1535123866, 3530526046, 8124227554, 18700618529, 43053766658, 99130762082, 228260731322

Offset

1,1

Links

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

Formula

Empirical: a(n) = 8*a(n-1) - 25*a(n-2) + 35*a(n-3) - 7*a(n-4) - 49*a(n-5) + 77*a(n-6) - 55*a(n-7) + 20*a(n-8) - 3*a(n-9) for n>12.

Empirical g.f.: x*(854 - 2498*x - 3033*x^2 + 21041*x^3 - 34325*x^4 + 22458*x^5 + 1073*x^6 - 9797*x^7 + 4718*x^8 - 398*x^9 - 153*x^10 + 3*x^11) / ((1 - x)^7*(1 - x - 3*x^2)). - Colin Barker, Nov 24 2018

Example

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

Crossrefs

Column 3 of A251055.

Sequence in context: A251148 A127593 A248856 * A085323 A185639 A105275

Adjacent sequences: A251047 A251048 A251049 * A251051 A251052 A251053

Keyword

nonn

Author

R. H. Hardin, Nov 29 2014

Status

approved