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A097165
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Expansion of (1-3x)/((1-x)(1-4x)(1-5x)).
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3
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1, 7, 41, 227, 1221, 6447, 33601, 173467, 889181, 4533287, 23015961, 116477907, 587981941, 2962279327, 14900875121, 74862289547, 375743103501, 1884442140567, 9445117195081, 47317211944387, 236952563597861
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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a(n)=5*5^n/2-4*4^n/3-1/6; a(n)=sum{k=0..n, (5^k+1)4^(n-k)/2}; a(n)=sum{k=0..n, (4^k+2)5^(n-k)/3}; a(n)=10a(n-1)-29a(n-2)+20a(n-3).
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MATHEMATICA
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CoefficientList[Series[(1-3x)/((1-x)(1-4x)(1-5x)), {x, 0, 30}], x] (* or *) LinearRecurrence[{10, -29, 20}, {1, 7, 41}, 30] (*Harvey P. Dale,Jan 24 2012 *)
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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