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Number of 5 X n 0..2 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two exactly once.
1

%I #6 Apr 10 2022 14:24:19

%S 0,6912,98496,1347192,17194680,214142760,2611960344,31382176824,

%T 372469407912,4376985056856,51011490408120,590386685589432,

%U 6792451934064264,77748739088317848,885979967930009496

%N Number of 5 X n 0..2 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two exactly once.

%C Row 5 of A268904.

%H R. H. Hardin, <a href="/A268908/b268908.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 32*a(n-1) -384*a(n-2) +2200*a(n-3) -6494*a(n-4) +9016*a(n-5) -816*a(n-6) -14888*a(n-7) +18879*a(n-8) -5464*a(n-9) -7472*a(n-10) +8336*a(n-11) -3648*a(n-12) +768*a(n-13) -64*a(n-14) for n>18.

%e Some solutions for n=3

%e ..2..2..1. .0..2..2. .2..1..2. .1..0..1. .2..1..2. .0..0..0. .2..1..0

%e ..2..0..1. .1..2..1. .2..1..0. .0..2..2. .0..2..1. .1..0..0. .2..1..0

%e ..1..2..1. .1..0..1. .0..0..1. .2..2..2. .1..2..2. .1..0..0. .2..1..0

%e ..1..0..0. .1..2..2. .1..2..2. .1..2..2. .1..2..2. .0..1..0. .2..1..2

%e ..0..0..0. .1..2..2. .1..1..0. .1..2..2. .2..2..1. .0..1..1. .0..0..0

%Y Cf. A268904.

%K nonn

%O 1,2

%A _R. H. Hardin_, Feb 15 2016