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A121709
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Numerator of Sum/Product of first n Lucas numbers A000032[n].
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1
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1, 4, 2, 5, 13, 1, 73, 5, 7, 1, 37, 5, 1361, 1, 223, 25, 4673, 1, 24473, 25, 16019, 1, 83879, 65, 62743, 1, 20533, 65, 1505173, 1, 7881193, 85, 5158309, 1, 27009259, 425, 1400221, 1, 1446283, 2225, 69237359, 1, 51790217, 445, 1660959719, 1, 8696897999
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OFFSET
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1,2
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COMMENTS
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5 divides a(4k). a(1) = 1 and a(4k+2) = 1 for k>0.
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LINKS
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FORMULA
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a(n) = Numerator[Sum[Lucas[k],{k,1,n}]/Product[Lucas[k],{k,1,n}]], where Lucas[k] = Fibonacci[k-1] + Fibonacci[k+1].
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MATHEMATICA
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Table[Numerator[Sum[Fibonacci[k-1]+Fibonacci[k+1], {k, 1, n}]/Product[Fibonacci[k-1]+Fibonacci[k+1], {k, 1, n}]], {n, 1, 100}]
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CROSSREFS
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KEYWORD
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frac,nonn
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AUTHOR
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STATUS
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approved
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