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A249999
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Expansion of 1/((1-x)^2*(1-2*x)*(1-3*x)).
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3
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1, 7, 32, 122, 423, 1389, 4414, 13744, 42245, 128771, 390396, 1179366, 3554467, 10696153, 32153978, 96592988, 290041089, 870647535, 2612991160, 7841070610, 23527406111, 70590606917, 211788597942, 635399348232, 1906265153533, 5718929678299, 17157057470324, 51471709281854
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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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G.f.: 1/((1-x)^2 * (1-2*x) * (1-3*x)).
a(n) = 9/4 - 2^(n+3) + n/2 + 3^(n+3)/4. - R. J. Mathar, Jan 09 2015
E.g.f.: (1/4)*((9 + 2*x) - 32*exp(x) + 27*exp(2*x))*exp(x). - G. C. Greubel, Jul 21 2022
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MATHEMATICA
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LinearRecurrence[{7, -17, 17, -6}, {1, 7, 32, 122}, 50] (* G. C. Greubel, Jul 21 2022 *)
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PROG
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(Magma) [(2*n +9 -2^(n+5) +3^(n+3))/4: n in [0..50]]; // G. C. Greubel, Jul 21 2022
(SageMath) [(2*n+9 -2^(n+5) +3^(n+3))/4 for n in (0..50)] # G. C. Greubel, Jul 21 2022
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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