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A253328
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Number of (3+1)X(n+1) 0..1 arrays with every 2X2 subblock sum nondecreasing horizontally, vertically and antidiagonally ne-to-sw
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1
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121, 377, 1217, 3787, 11506, 31999, 86922, 217799, 537127, 1242718, 2846066, 6208632, 13461284, 28145490, 58668559, 119104209, 241640885, 481269481, 959688428, 1890550722, 3733605722, 7319677531, 14396259965, 28207082638
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 4*a(n-1) +20*a(n-2) -98*a(n-3) -168*a(n-4) +1122*a(n-5) +674*a(n-6) -7970*a(n-7) -205*a(n-8) +39322*a(n-9) -13326*a(n-10) -142896*a(n-11) +86380*a(n-12) +395612*a(n-13) -325028*a(n-14) -850708*a(n-15) +867429*a(n-16) +1433880*a(n-17) -1752520*a(n-18) -1894178*a(n-19) +2759240*a(n-20) +1938970*a(n-21) -3430470*a(n-22) -1491450*a(n-23) +3380665*a(n-24) +795530*a(n-25) -2631230*a(n-26) -214060*a(n-27) +1599540*a(n-28) -65400*a(n-29) -744088*a(n-30) +104272*a(n-31) +255920*a(n-32) -56864*a(n-33) -61344*a(n-34) +17856*a(n-35) +9152*a(n-36) -3200*a(n-37) -640*a(n-38) +256*a(n-39)
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EXAMPLE
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Some solutions for n=4
..0..0..0..1..1....0..1..1..1..1....0..1..0..1..1....0..0..0..0..1
..0..1..0..0..0....0..1..0..1..0....0..0..0..0..0....0..0..0..0..0
..1..0..1..1..1....1..1..1..1..1....1..0..1..1..1....1..0..1..1..1
..0..1..0..1..1....1..0..1..0..1....0..1..0..1..1....0..0..1..0..1
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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