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A166060
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a(n) = 4*3^n - 3*2^n.
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9
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1, 6, 24, 84, 276, 876, 2724, 8364, 25476, 77196, 233124, 702444, 2113476, 6352716, 19082724, 57297324, 171990276, 516167436, 1548895524, 4647473004, 13943991876, 41835121356, 125511655524, 376547549484, 1129667814276
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OFFSET
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0,2
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COMMENTS
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Second binomial transform of A123932 = [1,4,4,4,4,4,4,4,...].
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LINKS
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FORMULA
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a(n) = 5*a(n-1) - 6*a(n-2) for n > 1; a(0)= 1, a(1)= 6.
G.f.: (1+x)/(1-5x+6x^2).
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MATHEMATICA
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CoefficientList[Series[(1+x)/((1-2x)*(1-3x)), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 05 2012 *)
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PROG
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(Haskell)
a166060 n = a166060_list !! n
a166060_list = map fst $ iterate (\(u, v) -> (3 * (u + v), 2 * v)) (1, 1)
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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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EXTENSIONS
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STATUS
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approved
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