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Search: id:A123183
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| A123183 |
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a(1)=-1; a(2)=-1; a(3)=-2; a(n)=4a(n-1)-3a(n-2) for n>=4. |
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+0
2
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| -1, -1, -2, -5, -14, -41, -122, -365, -1094, -3281, -9842, -29525, -88574, -265721, -797162, -2391485, -7174454, -21523361, -64570082, -193710245, -581130734, -1743392201, -5230176602, -15690529805, -47071589414, -141214768241, -423644304722, -1270932914165, -3812798742494
(list; graph; listen)
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OFFSET
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1,3
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FORMULA
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a(n)=-A124302(n-1). G.f.: -x*(1+3x+x^2)/(1-4x+3x^2). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Dec 05 2008]
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MAPLE
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a[1]:=-1: a[2]:=-1: a[3]:=-2: for n from 4 to 29 do a[n]:=4*a[n-1]-3*a[n-2] od: seq(a[n], n=1..29);
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MATHEMATICA
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M = {{1, -1, 0}, {-1, 2, -1}, {0, -1, 1}} v[1] = {1, 0, 0} v[n_] := v[n] = M.v[n - 1] a1 = Table[ -v[n][[1]], {n, 1, 50}]
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CROSSREFS
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Sequence in context: A116849 A007051 A124302 this_sequence A088355 A113485 A054391
Adjacent sequences: A123180 A123181 A123182 this_sequence A123184 A123185 A123186
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KEYWORD
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sign
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AUTHOR
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Roger Bagula (rlbagulatftn(AT)yahoo.com), Oct 02 2006
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com), Oct 08 2006
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