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A137229
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Expansion of g.f. x/((1-x)*(1-3*x+2*x^2-x^3)).
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8
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1, 4, 11, 27, 64, 150, 350, 815, 1896, 4409, 10251, 23832, 55404, 128800, 299425, 696080, 1618191, 3761839, 8745216, 20330162, 47261894, 109870575, 255418100, 593775045, 1380359511, 3208946544, 7459895656, 17342153392, 40315615409, 93722435100, 217878227875
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OFFSET
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1,2
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COMMENTS
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Previous name was: Transform of A000217 without the initial 0 by the T_{0,0} transformation (see link).
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LINKS
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FORMULA
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O.g.f: x/((1-x)*(1 -3*x +2*x^2 -x^3)).
a(n) = term (4,1) in the 4x4 matrix [3,1,0,0; -2,0,1,0; 1,0,0,0; 1,0,0,1]^(n). - Alois P. Heinz, Jul 24 2008
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MAPLE
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a:= n-> (<<3|1|0|0>, <-2|0|1|0>, <1|0|0|0>, <1|0|0|1>>^n)[4, 1]:
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MATHEMATICA
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LinearRecurrence[{4, -5, 3, -1}, {1, 4, 11, 27}, 40] (* Harvey P. Dale, Nov 10 2014 *)
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PROG
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(Magma) I:=[1, 4, 11, 27]; [n le 4 select I[n] else 4*Self(n-1) -5*Self(n-2) +3*Self(n-3) -Self(n-4): n in [1..40]]; // G. C. Greubel, Apr 17 2021
(Sage)
P.<x> = PowerSeriesRing(ZZ, prec)
return P( x/((1-x)*(1-3*x+2*x^2-x^3)) ).list()
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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