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A168611
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a(n) = 3^n - 4.
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3
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-3, -1, 5, 23, 77, 239, 725, 2183, 6557, 19679, 59045, 177143, 531437, 1594319, 4782965, 14348903, 43046717, 129140159, 387420485, 1162261463, 3486784397, 10460353199, 31381059605, 94143178823, 282429536477, 847288609439
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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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a(n) = 3*a(n-1) + 8 with a(0)=-3.
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MATHEMATICA
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CoefficientList[Series[(11*x-3)/((1-x)*(1-3*x)), {x, 0, 40}], x] (* Vincenzo Librandi, Jul 06 2012 *)
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PROG
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(Magma) I:=[-3, -1]; [n le 2 select I[n] else 4*Self(n-1)-3*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Jul 06 2012
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CROSSREFS
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KEYWORD
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sign,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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