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A083315
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a(n) = (2*5^n-(4^n-2^n))/2.
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2
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1, 4, 19, 97, 505, 2629, 13609, 69997, 357985, 1822309, 9241849, 46731997, 235754065, 1187152789, 5969306089, 29980723597, 150440439745, 754349584069, 3780337658329, 18936047636797, 94817676351025, 474638135996149
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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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G.f.: (1-7*x+13*x^2)/((1-2*x)*(1-4*x)*(1-5*x)).
E.g.f.: (2*exp(5*x)-exp(4*x)+exp(2*x))/2.
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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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