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Search: id:A135446
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| A135446 |
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a(n)=3a(n-1)-3a(n-2)+2a(n-3). |
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+0
1
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| -1, -1, 3, 10, 19, 33, 62, 125, 255, 514, 1027, 2049, 4094, 8189, 16383, 32770, 65539, 131073, 262142, 524285, 1048575, 2097154, 4194307, 8388609, 16777214, 33554429, 67108863, 134217730, 268435459, 536870913, 1073741822
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Sequence identical to its third differences.
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FORMULA
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a(n+1)-2a(n) = hexaperiodic 1, 5, 4, -1, -5, -4, A130815.
a(n) = 2^n-2*cos((Pi*n)/3)-(4*3^0.5/3)*sin((Pi*n)/3). Or, a(n)=2^n + [ -2; -3; -1; 2; 3; 1]. - Richard Choulet (richardchoulet(AT)yahoo.fr), Dec 31 2007
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MATHEMATICA
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a = {-1, -1, 3}; Do[AppendTo[a, 3*a[[ -1]] - 3*a[[ -2]] + 2*a[[ -3]]], {40}]; a - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 22 2007
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CROSSREFS
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Sequence in context: A064027 A028878 A010896 this_sequence A160002 A027177 A048343
Adjacent sequences: A135443 A135444 A135445 this_sequence A135447 A135448 A135449
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KEYWORD
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sign
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AUTHOR
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Paul Curtz (bpcrtz(AT)free.fr), Dec 13 2007
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EXTENSIONS
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More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 22 2007
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