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A330390
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G.f.: (1 + 15*x) / (1 - 2*x - 17*x^2).
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1
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1, 17, 51, 391, 1649, 9945, 47923, 264911, 1344513, 7192513, 37241747, 196756215, 1026622129, 5398099913, 28248776019, 148265250559, 776759693441, 4074028646385, 21352972081267, 111964431151079, 586929387683697, 3077254104935737, 16132307800494323
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = 2*a(n-1) + 17*a(n-2) for n>1.
a(n)/a(n-1) ~ 1 + 3*sqrt(2).
a(n) = ((1 - 3*sqrt(2))^n*(-16+3*sqrt(2)) + (1+3*sqrt(2))^n*(16 + 3*sqrt(2))) / (6*sqrt(2)). - Colin Barker, Dec 14 2019
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MATHEMATICA
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CoefficientList[Series[(1+15x)/(1-2x-17x^2), {x, 0, 30}], x] (* or *) LinearRecurrence[{2, 17}, {1, 17}, 30] (* Harvey P. Dale, Jul 31 2021 *)
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PROG
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(PARI) Vec((1 + 15*x) / (1 - 2*x - 17*x^2) + O(x^25)) \\ Colin Barker, Jan 25 2020
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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