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A028170
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Expansion of 1/((1-5x)(1-6x)(1-8x)(1-9x)).
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1
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1, 28, 495, 7070, 89201, 1038408, 11432275, 120872290, 1239829701, 12425000588, 122271240455, 1185943687110, 11369353359001, 107963322279568, 1017222704311035, 9522095291175530, 88651748959581101
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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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a(n) = 28*a(n-1) - 289*a(n-2) + 1302*a(n-3) - 2160*a(n-4). - Vincenzo Librandi, Feb 23 2012
a(n) = (9^(n+3) - 2*8^(n+3) + 2*6^(n+3) - 5^(n+3))/12. - Yahia Kahloune, Jun 03 2013
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MATHEMATICA
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CoefficientList[Series[1/((1-5x)(1-6x)(1-8x)(1-9x)), {x, 0, 20}], x] (* Vincenzo Librandi, Feb 23 2012 *)
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PROG
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(Magma) I:=[1, 28, 495, 7070]; [n le 4 select I[n] else 28*Self(n-1)-289*Self(n-2)+1302*Self(n-3)-2160*Self(n-4): n in [1..40]]; // Vincenzo Librandi, Feb 23 2012
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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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