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CoefficientList[Series[(1+11x-11x^2+4x^3)/(1-3x+x^2)^2, {x, 0, 30}], x] (* Harvey P. Dale, Aug 28 2021 *)
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É. Czabarka, R. Flórez, and L. Junes, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL18/Florez/florez12.html">A Discrete Convolution on the Generalized Hosoya Triangle</a>, Journal of Integer Sequences, 18 (2015), #15.1.6.
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G.f.: (1 + 11*x - 11*x^2 + 4*x^3)/(1 - 3*x + x^2)^2.
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Numerator of g.f. is row polynomial sum(Sum_{m=0..3} A061186(2, m)*x^m,m=0..3).
G. C. Greubel, <a href="/A060934/b060934.txt">Table of n, a(n) for n = 0..1000</a>
<a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (6,-11,6,-1).
G.f.: (1 +11*x -11*x^2 +4*x^3)/(1-3*x+x^2)^2.
a(n) = 2*n*Lucas(2*n+2) + Fibonacci(2*n+2). - G. C. Greubel, Apr 09 2021
LinearRecurrence[{6, -11, 6, -1}, {1, 17, 80, 303}, 31] (* G. C. Greubel, Apr 09 2021 *)
(Magma) [2*n*Lucas(2*n+2) + Fibonacci(2*n+2): n in [0..30]]; // G. C. Greubel, Apr 09 2021
(Sage) [2*n*lucas_number2(2*n+2, 1, -1) + fibonacci(2*n+2) for n in (0..30)] # G. C. Greubel, Apr 09 2021
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