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A235417 Number of (n+1)X(1+1) 0..2 arrays with 2X2 subblock sum of squares lexicographically nondecreasing rowwise and nonincreasing columnwise 2

%I

%S 81,432,2304,9504,39204,138402,488601,1553877,4941729,14587326,

%T 43059844,120242088,335768976,898407396,2403842841,6218691273,

%U 16087624569,40503112884,101972926224,251077339656,618201642564,1494166176558

%N Number of (n+1)X(1+1) 0..2 arrays with 2X2 subblock sum of squares lexicographically nondecreasing rowwise and nonincreasing columnwise

%C Column 1 of A235421

%H R. H. Hardin, <a href="/A235417/b235417.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) +12*a(n-2) -138*a(n-3) +44*a(n-4) +1362*a(n-5) -1706*a(n-6) -7446*a(n-7) +14669*a(n-8) +23808*a(n-9) -69362*a(n-10) -39576*a(n-11) +208600*a(n-12) -417200*a(n-14) +158304*a(n-15) +554896*a(n-16) -380928*a(n-17) -469408*a(n-18) +476544*a(n-19) +218368*a(n-20) -348672*a(n-21) -22528*a(n-22) +141312*a(n-23) -24576*a(n-24) -24576*a(n-25) +8192*a(n-26)

%e Some solutions for n=5

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

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 10 2014

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Last modified January 27 23:41 EST 2022. Contains 350654 sequences. (Running on oeis4.)