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T(n,k)=Number of (n+1)X(k+1) 0..5 arrays with every 2X2 subblock having equal diagonal elements or equal antidiagonal elements
9

%I #5 Mar 31 2012 12:37:00

%S 396,4356,4356,47916,106596,47916,527076,2543436,2543436,527076,

%T 5797836,60873876,140120856,60873876,5797836,63776196,1456391916,

%U 7748585676,7748585676,1456391916,63776196,701538156,34845401556,428652828396

%N T(n,k)=Number of (n+1)X(k+1) 0..5 arrays with every 2X2 subblock having equal diagonal elements or equal antidiagonal elements

%C Table starts

%C ........396...........4356.............47916................527076

%C .......4356.........106596...........2543436..............60873876

%C ......47916........2543436.........140120856............7748585676

%C .....527076.......60873876........7748585676.........1012872412476

%C ....5797836.....1456391916......428652828396.......132923754354276

%C ...63776196....34845401556....23714024087016.....17475349695161076

%C ..701538156...833700866796..1311917257647036...2297197186864332876

%C .7716919716.19946896311636.72578467770478956.302046352349437619676

%H R. H. Hardin, <a href="/A203934/b203934.txt">Table of n, a(n) for n = 1..84</a>

%F Empirical for row k:

%F k=1: a(n) = 36*11^n

%F k=2: a(n) = 21*a(n-1) +70*a(n-2)

%F k=3: a(n) = 61*a(n-1) -315*a(n-2) +50*a(n-3)

%F k=4: a(n) = 91*a(n-1) +7335*a(n-2) -264625*a(n-3) -85500*a(n-4) +10470000*a(n-5) +2475000*a(n-6) -20750000*a(n-7)

%F k=5: (order 12 recurrence)

%e Some solutions for n=4 k=3

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

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

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

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

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

%K nonn,tabl

%O 1,1

%A _R. H. Hardin_ Jan 08 2012