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1/729 the number of (n+2)X4 0..2 arrays with each 3X3 subblock trace equal to some horizontal or vertical neighbor 3X3 subblock trace
1

%I #5 Mar 31 2012 12:36:07

%S 141,3783,112707,3277141,97400287,2888274935,85776954369,

%T 2546947279751,75630536807503,2245787022119429,66687334739920767,

%U 1980238746462258727,58801972365560118385,1746088100799717075951,51849007300503734099607

%N 1/729 the number of (n+2)X4 0..2 arrays with each 3X3 subblock trace equal to some horizontal or vertical neighbor 3X3 subblock trace

%C Column 2 of A186962

%H R. H. Hardin, <a href="/A186955/b186955.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n)=47*a(n-1)-768*a(n-2)+9074*a(n-3)-45676*a(n-4)-128151*a(n-5)+5533509*a(n-6)-52222861*a(n-7)+298891037*a(n-8)-1210990268*a(n-9)+3279669868*a(n-10)-17103854630*a(n-11)+107074386692*a(n-12)-1120651976017*a(n-13)+7699882976383*a(n-14)-33134456122091*a(n-15)+92437597748240*a(n-16)+38779112318679*a(n-17)-1551804761709560*a(n-18)+9965097308686132*a(n-19)-50284950459235995*a(n-20)+179585137427153085*a(n-21)-578474821841140342*a(n-22)+1942680073913443282*a(n-23)-5027762409706958859*a(n-24)+9396977935434079200*a(n-25)-20206920616774402097*a(n-26)+58961273014571044815*a(n-27)-112421473018387267444*a(n-28)+93462257273423718410*a(n-29)-316402182009678573237*a(n-30)+1531066228189153802915*a(n-31)-2686718460318211032026*a(n-32)+2053586264368753695435*a(n-33)-2076958606567745248818*a(n-34)+1937582374265499138858*a(n-35)+7404451721545153252536*a(n-36)-18194558603000114302344*a(n-37)+9731906357545639525338*a(n-38)-10025123117175587171682*a(n-39)+46821629047289151838716*a(n-40)-45792793514173775732496*a(n-41)-1506342726304390998216*a(n-42)-24094079332639271890128*a(n-43)+74005028615171054189376*a(n-44)-33748481066062903349760*a(n-45)-2412084047728654817280*a(n-46)-29576127381131851372800*a(n-47)+45681436873259623123200*a(n-48)-23580992522523885120000*a(n-49)+5680081947509907840000*a(n-50)-1045093802418288000000*a(n-51)+196518268204272000000*a(n-52)

%e Some solutions for 6X4

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

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 01 2011