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A049863
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a(n)=Sum{a(k): k=0,1,2,...,n-4,n-2,n-1}; a(n-3) is not a summand; 3 initial terms required.
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1
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0, 3, 4, 7, 11, 21, 39, 74, 138, 258, 481, 898, 1676, 3129, 5841, 10904, 20355, 37998, 70933, 132415, 247187, 461439, 861396, 1608020, 3001788, 5603619, 10460614, 19527460, 36453089, 68049183, 127031520, 237137411, 442678728
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n)=2*a(n-1)-a(n-3)+a(n-4); 4 initial terms required.
G.f.: (x^3+2x^2-3x)/(x^4-x^3+2x-1). - _Harvey P. Dale, Apr 26 2011
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MATHEMATICA
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LinearRecurrence[{2, 0, -1, 1}, {0, 3, 4, 7}, 40] (* or *) CoefficientList[ Series[(x^3+2x^2-3x)/(x^4-x^3+2x-1), {x, 0, 50}], x] (* Harvey P. Dale, Apr 26 2011 *)
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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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