A185848 Number of (n+1) X 2 0..2 arrays with no 2 X 2 subblock diagonal sum less antidiagonal sum equal to any horizontal or vertical neighbor 2 X 2 subblock diagonal sum less antidiagonal sum.

81, 630, 4942, 38700, 303212, 2375550, 18611050, 145808838, 1142339588, 8949663042, 70116185140, 549325551516, 4303693552406, 33717306885174, 264158394384970, 2069550147728712, 16213900082399138, 127027874230202640

Offset

1,1

Comments

Column 1 of A185856.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 3*a(n-1) + 20*a(n-2) + 99*a(n-3) + 252*a(n-4) + 510*a(n-5) + 324*a(n-6) - 336*a(n-7) - 288*a(n-8).

Empirical g.f.: x*(81 + 387*x + 1432*x^2 + 3255*x^3 + 5490*x^4 + 2586*x^5 - 4068*x^6 - 3024*x^7) / (1 - 3*x - 20*x^2 - 99*x^3 - 252*x^4 - 510*x^5 - 324*x^6 + 336*x^7 + 288*x^8). - Colin Barker, Apr 17 2018

Example

Some solutions for 3 X 2:
..2..1....0..2....2..0....2..0....0..1....2..0....0..1....1..2....1..1....0..0
..0..2....1..0....0..2....0..0....2..1....0..1....2..1....0..2....1..1....2..1
..0..1....1..1....1..0....1..1....2..2....1..1....1..0....1..2....2..0....2..1

Crossrefs

Cf. A185856.

Sequence in context: A256590 A322240 A185856 * A237629 A236720 A187441

Adjacent sequences: A185845 A185846 A185847 * A185849 A185850 A185851

Keyword

nonn

Author

R. H. Hardin, Feb 05 2011

Status

approved