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A270567
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Expansion of (1+4*x)/(1-5*x).
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2
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1, 9, 45, 225, 1125, 5625, 28125, 140625, 703125, 3515625, 17578125, 87890625, 439453125, 2197265625, 10986328125, 54931640625, 274658203125, 1373291015625, 6866455078125, 34332275390625, 171661376953125, 858306884765625, 4291534423828125, 21457672119140625
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OFFSET
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0,2
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COMMENTS
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Partial sums are 1, 10, 55, 280, 1405, 7030, ...
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LINKS
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FORMULA
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G.f.: (1+4*x) / (1-5*x).
a(n) = 5*a(n-1) for n>1.
a(n) = 9*5^(n-1) for n>0.
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MATHEMATICA
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CoefficientList[Series[(1 + 4 x)/(1 - 5 x), {x, 0, 23}], x] (* Michael De Vlieger, Mar 19 2016 *)
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PROG
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(PARI) Vec((1+4*x)/(1-5*x) + O(x^30))
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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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