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Number of nX7 0..2 arrays with some element plus some horizontally or vertically adjacent neighbor totalling two no more than once.
1

%I #4 Feb 09 2016 09:24:08

%S 768,29646,982086,30553014,915847266,26758514760,767057092212,

%T 21665715966234,604770363515718,16719464029955466,458539471622171262,

%U 12491032205839395768,338309651358216576312,9117289065936178169226

%N Number of nX7 0..2 arrays with some element plus some horizontally or vertically adjacent neighbor totalling two no more than once.

%C Column 7 of A268628.

%H R. H. Hardin, <a href="/A268627/b268627.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 110*a(n-1) -5243*a(n-2) +144650*a(n-3) -2610593*a(n-4) +33017408*a(n-5) -305811128*a(n-6) +2137462184*a(n-7) -11513372884*a(n-8) +48502300256*a(n-9) -161412354008*a(n-10) +427044616576*a(n-11) -901108804624*a(n-12) +1517344261024*a(n-13) -2035022988048*a(n-14) +2164824966496*a(n-15) -1815145078160*a(n-16) +1189730382208*a(n-17) -603502277248*a(n-18) +234173991424*a(n-19) -68574152448*a(n-20) +14906358784*a(n-21) -2352277504*a(n-22) +260550656*a(n-23) -19140608*a(n-24) +835584*a(n-25) -16384*a(n-26)

%e Some solutions for n=2

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

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

%Y Cf. A268628.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 09 2016