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A145976
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Expansion of 1/(1-x*(1-7*x)).
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8
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1, 1, -6, -13, 29, 120, -83, -923, -342, 6119, 8513, -34320, -93911, 146329, 803706, -220597, -5846539, -4302360, 36623413, 66739933, -189623958, -656803489, 670564217, 5268188640, 574239121, -36303081359, -40322755206, 213798814307
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OFFSET
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0,3
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COMMENTS
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Row sums of Riordan array (1,x(1-7x)).
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LINKS
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FORMULA
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a(n) = a(n-1) - 7*a(n-2), a(0)=1, a(1)=1.
a(n) = Sum_{k=0..n} A109466(n,k)*7^(n-k).
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MATHEMATICA
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CoefficientList[Series[1/(1-x(1-7x)), {x, 0, 50}], x] (* or *) LinearRecurrence[{1, -7}, {1, 1}, 50] (* Harvey P. Dale, May 11 2011 *)
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PROG
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(Sage) [lucas_number1(n, 1, 7) for n in range(1, 29)] # Zerinvary Lajos, Apr 22 2009
(PARI) Vec(1/(1-x*(1-7*x)) + O(x^40)) \\ Michel Marcus, Jan 29 2016
(Magma) I:=[1, 1]; [n le 2 select I[n] else Self(n-1) - 7*Self(n-2): n in [1..30]]; // G. C. Greubel, Jan 19 2018
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CROSSREFS
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KEYWORD
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sign,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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