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%I #10 May 03 2023 18:02:57
%S 5,216,3096,39784,462680,5145736,55265336,580002280,5978552216,
%T 60784629832,611189228792,6090202880680,60229576820312,
%U 591855697435912,5784216137341880,56261693581866856,544976552619855128
%N Number of n X 2 0..4 arrays with some element plus some horizontally, diagonally, antidiagonally or vertically adjacent neighbor totaling four exactly once.
%H R. H. Hardin, <a href="/A269823/b269823.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 10*a(n-1) + 47*a(n-2) - 336*a(n-3) - 1416*a(n-4) - 864*a(n-5) - 144*a(n-6) for n>7.
%F Empirical g.f.: x*(5 + 166*x + 701*x^2 + 352*x^3 - 1016*x^4 - 480*x^5 + 720*x^6) / (1 - 5*x - 36*x^2 - 12*x^3)^2. - _Colin Barker_, Jan 29 2019
%e Some solutions for n=4:
%e ..4..2. .2..0. .1..1. .3..3. .1..4. .4..2. .1..1. .3..3. .2..4. .2..3
%e ..1..4. .0..3. .4..2. .2..2. .2..0. .1..1. .2..0. .4..4. .3..0. .0..4
%e ..1..2. .2..0. .3..0. .4..4. .0..0. .4..2. .1..2. .2..1. .3..3. .1..1
%e ..2..0. .4..3. .3..0. .4..4. .1..2. .3..2. .1..4. .0..2. .2..0. .2..1
%Y Column 2 of A269829.
%K nonn
%O 1,1
%A _R. H. Hardin_, Mar 05 2016
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