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A280310
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Number of nX3 0..2 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
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1
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0, 15, 788, 20274, 415198, 7506237, 125467047, 1986983748, 30245976536, 446674283782, 6440490980290, 91079336462727, 1267501948747806, 17402523729978130, 236196006568440774, 3174051771081117585
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 30*a(n-1) -222*a(n-2) -734*a(n-3) +8955*a(n-4) +17679*a(n-5) -93547*a(n-6) -212481*a(n-7) +239184*a(n-8) +1034132*a(n-9) +1156653*a(n-10) -1089108*a(n-11) -5976636*a(n-12) -5117229*a(n-13) +2977569*a(n-14) +11073336*a(n-15) +13515996*a(n-16) -4312494*a(n-17) -13983961*a(n-18) -6912540*a(n-19) -1327035*a(n-20) +13168450*a(n-21) -1804992*a(n-22) -4913097*a(n-23) +761601*a(n-24) -310968*a(n-25) +2250468*a(n-26) -46384*a(n-27) -448224*a(n-28) +213120*a(n-29) -8640*a(n-30) +157440*a(n-31) +4608*a(n-32) -12288*a(n-33) +9216*a(n-34) +4096*a(n-36) for n>38
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EXAMPLE
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Some solutions for n=4
..0..0..1. .0..1..0. .0..1..2. .0..0..0. .0..1..0. .0..1..0. .0..1..1
..1..0..0. .0..0..2. .2..1..0. .1..0..1. .1..1..1. .0..2..1. .0..2..0
..1..2..2. .2..0..2. .0..0..0. .2..2..2. .2..0..2. .0..2..2. .1..1..2
..0..1..1. .2..1..1. .2..1..2. .0..2..1. .1..0..0. .2..1..1. .2..2..2
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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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