A269210 Number of n X 4 0..3 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling three exactly once.

108, 6528, 308544, 12548544, 474091776, 17118725376, 599456856000, 20531285093184, 691495131961728, 22985647571590272, 756022683316823616, 24651356966323488960, 797979183054277922304, 25672248307708057755648

Offset: 1

Author

R. H. Hardin, Feb 20 2016

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Column 4 of A269214.

Formula

Empirical: a(n) = 62*a(n-1) - 1031*a(n-2) + 2180*a(n-3) - 1535*a(n-4) + 350*a(n-5) - 25*a(n-6) for n>7.

Empirical g.f.: 12*x*(9 - 14*x + 1263*x^2 - 7188*x^3 + 10471*x^4 - 4926*x^5 + 897*x^6) / ((1 - x)^2*(1 - 30*x + 5*x^2)^2). - Colin Barker, Jan 20 2019