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A185536 1/6 the number of nX3 0..5 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors 1

%I #7 Mar 31 2012 12:36:02

%S 1,110,2990,127570,4403225,167398110,6079401960,225574291125,

%T 8285469213945,305786452982260,11260066599241195,415073544779136460,

%U 15292958690004125565,563586551260018728505,20767361004817999220125

%N 1/6 the number of nX3 0..5 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors

%C Column 3 of A185540

%H R. H. Hardin, <a href="/A185536/b185536.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n)=22*a(n-1)+638*a(n-2)-2567*a(n-3)-29583*a(n-4)+27088*a(n-5)+209637*a(n-6)+620796*a(n-7)-1634411*a(n-8)-4083145*a(n-9)+17086070*a(n-10)-21827225*a(n-11)-42404829*a(n-12)-73933685*a(n-13)+687497360*a(n-14)-669370750*a(n-15)-1844490625*a(n-16)+8145764375*a(n-17)+6297734375*a(n-18)-14443984375*a(n-19)-34831953125*a(n-20)-42570312500*a(n-21)-47656250000*a(n-22)-78125000000*a(n-23)

%e Some solutions for 5X3 with a(1,1)=0

%e ..0..0..0....0..0..0....0..0..3....0..0..3....0..0..0....0..0..0....0..3..3

%e ..0..3..3....0..3..3....0..0..3....0..3..3....0..3..3....0..3..3....0..0..0

%e ..4..0..0....4..1..3....3..3..1....1..0..0....0..2..2....2..2..3....5..2..0

%e ..4..4..4....4..1..0....5..5..1....1..1..2....3..4..2....2..4..0....5..2..2

%e ..5..5..4....0..0..0....4..4..4....5..5..2....3..4..4....2..4..0....5..5..5

%K nonn

%O 1,2

%A _R. H. Hardin_ Jan 30 2011

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Last modified February 24 08:44 EST 2024. Contains 370294 sequences. (Running on oeis4.)