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1, 4, 9, 36, 81, 324, 729, 2916, 6561, 26244, 59049, 236196, 531441, 2125764, 4782969, 19131876, 43046721, 172186884, 387420489, 1549681956, 3486784401, 13947137604, 31381059609, 125524238436, 282429536481, 1129718145924, 2541865828329, 10167463313316
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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A133080 * A000244, where A000244 = (3^0, 3^1, 3^2, ...). For even n, a(n) = 3^n. For odd n, a(n) = 4 * 3^(n-1).
G.f.: (1+4x)/((1+3x)(1-3x)). a(n) = 9*a(n-2). - R. J. Mathar, Oct 30 2008
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EXAMPLE
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a(4) = 3^4 = 81.
a(5) = 324 = 4 * 3^4.
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MATHEMATICA
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LinearRecurrence[{0, 9}, {1, 4}, 30] (* Harvey P. Dale, Mar 27 2017 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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