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A252863
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Number of Eulerian paths in a lattice graph bounded by the four equations x+y=1, x+y=2n, x-y=2, and x-y=-2.
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1
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1, 16, 304, 5824, 111616, 2139136, 40996864, 785711104, 15058272256, 288594067456, 5530948993024, 106001474781184, 2031534311735296, 38934662638206976, 746188703776374784, 14300819473316184064, 274077370205901684736, 5252734292544974749696
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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 g.f.: (x - 4*x^2)/(1 - 20*x + 16*x^2) and recurrence a(n) = 20*a(n-1) - 16*a(n-2). - Robert Israel, Dec 26 2014
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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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