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A177844
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a(n) = 6*a(n-1)-8*a(n-2) for n > 3; a(0)=279, a(1)=3996, a(2)=16008, a(3)=64784.
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5
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279, 3996, 16008, 64784, 260640, 1045568, 4188288, 16765184, 67084800, 268387328, 1073645568, 4294774784, 17179484160, 68718706688, 274876366848, 1099508547584, 4398040350720, 17592173723648, 70368719536128
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OFFSET
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0,1
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COMMENTS
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Related to Reverse and Add trajectory of 775 in base 2: a(n) = A077077(4*n+1)/6, i.e. one sixth of second quadrisection of A077077.
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LINKS
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FORMULA
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a(n) = 4^(n+5)-47*2^(n+1) for n > 1.
G.f.: (279+2322*x-5736*x^2+704*x^3) / ((1-2*x)*(1-4*x)).
G.f. for the sequence starting at a(2): 8*x^2*(2001-3908*x)/((1-2*x)*(1-4*x)).
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MATHEMATICA
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CoefficientList[Series[(279 + 2322 x - 5736 x^2 + 704 x^3)/((1 - 2 x) (1 - 4 x)), {x, 0, 40}], x] (* Vincenzo Librandi, Sep 24 2013 *)
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PROG
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(PARI) {m=19; v=concat([279, 3996, 16008, 64784], vector(m-4)); for(n=5, m, v[n]=6*v[n-1]-8*v[n-2]); v}
(Magma) [279, 3996] cat [4^(n+5)-47*2^(n+1): n in [2..25]]; // Vincenzo Librandi, Sep 24 2013
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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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