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

1,1

Links

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

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

Example

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

Crossrefs

Column 4 of A269214.

Sequence in context: A147821 A269148 A143403 * A299857 A132053 A273439

Adjacent sequences: A269207 A269208 A269209 * A269211 A269212 A269213

Keyword

nonn

Author

R. H. Hardin, Feb 20 2016

Status

approved