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A328333
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Expansion of (1 + 4*x - 6*x^2) / ((1 - x) * (1 - 10*x^2)).
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2
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1, 5, 9, 49, 89, 489, 889, 4889, 8889, 48889, 88889, 488889, 888889, 4888889, 8888889, 48888889, 88888889, 488888889, 888888889, 4888888889, 8888888889, 48888888889, 88888888889, 488888888889, 888888888889, 4888888888889, 8888888888889, 48888888888889, 88888888888889
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OFFSET
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0,2
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COMMENTS
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Number of even palindromes < 10^n.
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LINKS
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MATHEMATICA
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nmax = 28; CoefficientList[Series[(1 + 4 x - 6 x^2)/((1 - x) (1 - 10 x^2)), {x, 0, nmax}], x]
LinearRecurrence[{1, 10, -10}, {1, 5, 9}, 29]
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PROG
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(PARI) Vec((1 + 4*x - 6*x^2) / ((1 - x) * (1 - 10*x^2)) + O(x^30)) \\ Michel Marcus, Oct 13 2019
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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