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 A205408 Number of (n+2)X3 0..2 arrays with every 3X3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly two ways, and new values 0..2 introduced in row major order 1

%I

%S 468,3868,33322,236576,1820215,14452683,109757792,844627201,

%T 6555663807,50395116296,388310279461,2998496455277,23106198583152,

%U 178125506630869,1373888878002903,10592170949339668,81666691848271821,629737361145882421

%N Number of (n+2)X3 0..2 arrays with every 3X3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly two ways, and new values 0..2 introduced in row major order

%C Column 1 of A205415

%H R. H. Hardin, <a href="/A205408/b205408.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) +15*a(n-2) +210*a(n-3) -46*a(n-4) -1180*a(n-5) -8860*a(n-6) -9460*a(n-7) +35477*a(n-8) +165003*a(n-9) +271917*a(n-10) -292806*a(n-11) -1718502*a(n-12) -2698834*a(n-13) -1465296*a(n-14) +4872048*a(n-15) +13801984*a(n-16) +30802224*a(n-17) +54371712*a(n-18) +14213752*a(n-19) -115878688*a(n-20) -314261840*a(n-21) -579542448*a(n-22) -599435264*a(n-23) +450034176*a(n-24) +2993109568*a(n-25) +6140523968*a(n-26) +5188675584*a(n-27) -5040264704*a(n-28) -21090059008*a(n-29) -30058399232*a(n-30) -12075326464*a(n-31) +39301468160*a(n-32) +79235510272*a(n-33) +29768392704*a(n-34) -75591352320*a(n-35) -84606517248*a(n-36) +10132783104*a(n-37) +59464876032*a(n-38) +26931363840*a(n-39)

%e Some solutions for n=3

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Jan 26 2012

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Last modified January 19 00:22 EST 2022. Contains 350464 sequences. (Running on oeis4.)