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A094688
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Convolution of Fibonacci(n) and 3^n.
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6
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0, 1, 4, 14, 45, 140, 428, 1297, 3912, 11770, 35365, 106184, 318696, 956321, 2869340, 8608630, 25826877, 77482228, 232449268, 697351985, 2092062720, 6276199106, 18828615029, 56485873744, 169457667600, 508373077825, 1525119354868
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OFFSET
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0,3
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LINKS
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FORMULA
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G.f.: x/((1-3*x)*(1-x-x^2)).
a(n) = (1/5)*(3^(n+1) - Lucas(n+2)).
a(n) = 4*a(n-1) - 2*a(n-2) - 3*a(n-3).
a(n) = a(n-1) + a(n-2) + 3^(n-1) for n > 1, with a(0) = 0, a(1) = 1. - Ross La Haye, Aug 20 2005
a(n) = 3*a(n-1) + Fibonacci(n), where a(0) = 0. - Taras Goy, Mar 24 2019
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MATHEMATICA
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PROG
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(Magma) I:=[0, 1, 4]; [n le 3 select I[n] else 4*Self(n-1)-2*Self(n-2) -3*Self(n-3): n in [1..41]]; // Vincenzo Librandi, Jun 24 2012
(SageMath) [(3^(n+1) -lucas_number2(n+2, 1, -1))/5 for n in range(41)] # G. C. Greubel, Feb 09 2023
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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