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2, 17, 130, 940, 6550, 44475, 296250, 1944375, 12612500, 81035000, 516537500, 3270615625, 20591031250, 128998328125, 804673593750, 5000444062500, 30969644531250, 191231146484375, 1177627753906250, 7234317013671875, 44342955390625000, 271252632343750000
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refs;
listen;
history;
text;
internal format)
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OFFSET
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0,1
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LINKS
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FORMULA
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G.f.: -(((1 + x) (-2 + 5 x + 5 x^2))/(-1 + 5 x + 5 x^2)^2).
a(n) = 10*a(n-1) - 15*a(n-2) - 50*a(n-3) - 25*a(n-4) for n >= 5.
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MATHEMATICA
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z = 60; s = x + x^2; p = (1 - 5 s)^2;
Drop[CoefficientList[Series[s, {x, 0, z}], x], 1] (* A019590 *)
u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1] (* A291389 *)
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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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