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A163038
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Number of nX3 binary arrays with all 1s connected and a path of 1s from left column to right column
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2
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1, 17, 144, 920, 5191, 27651, 143342, 733512, 3730303, 18914231, 95766768, 484557538, 2450951157, 12395284963, 62682479764, 316971668262, 1602829696167, 8104958759329, 40983832221302, 207239970377650, 1047934399198859
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OFFSET
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1,2
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LINKS
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FORMULA
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Empirical: a(n)= 12*a(n-1) -54*a(n-2) +121*a(n-3) -144*a(n-4) +72*a(n-5) +38*a(n-6) -82*a(n-7) +41*a(n-8) +4*a(n-9) -8*a(n-10) +a(n-11). G.f.: -x*(1+5*x-6*x^2-11*x^3+14*x^4-9*x^5-2*x^6-x^7+x^8) /( (x^2+2*x-1) *(x^6-7*x^5 +x^4+6*x^3-11*x^2+7*x-1) *(x-1)^3). [From R. J. Mathar, Aug 11 2009]
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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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