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A138233
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a(n) = 2^(2*n+1) + 3^(2*n+1).
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2
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5, 35, 275, 2315, 20195, 179195, 1602515, 14381675, 129271235, 1162785755, 10462450355, 94151567435, 847322163875, 7625731702715, 68630914235795, 617675543767595, 5559069156490115, 50031579458738075, 450284043329950835
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OFFSET
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0,1
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COMMENTS
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LINKS
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FORMULA
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a(n+1) = 4*a(n) + 5*3^(2*n+1), a(0) = 5.
O.g.f.: 5*x*(7-36*x)/((1-4*x)*(1-9*x)). - R. J. Mathar, Apr 24 2008
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MATHEMATICA
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LinearRecurrence[{13, -36}, {5, 35}, 19] (* Ray Chandler, Jul 14 2017 *)
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PROG
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(Magma) [2^(2*n+1) + 3^(2*n+1): n in [0..30]]; // G. C. Greubel, Mar 11 2023
(SageMath) [2^(2*n+1) + 3^(2*n+1) for n in range(31)] # G. C. Greubel, Mar 11 2023
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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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