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A188168
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a(0) = a(1) = 1; a(n) = 5*a(n-1) + 5*a(n-2).
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3
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1, 1, 10, 55, 325, 1900, 11125, 65125, 381250, 2231875, 13065625, 76487500, 447765625, 2621265625, 15345156250, 89832109375, 525886328125, 3078592187500, 18022392578125, 105504923828125, 617636582031250, 3615707529296875, 21166720556640625
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OFFSET
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0,3
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COMMENTS
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First differences give {0,9,45,270,1575,9225,54000,316125,1850625,10833750,63421875,371278125, . . .}
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LINKS
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FORMULA
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G.f.: (4x-1)/(5x^2+5x-1)
a(n) = 1/5 2^-n (-(5-3 Sqrt[5])^n (2+Sqrt[5])+(-2+Sqrt[5]) (5+3 Sqrt[5])^n)
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MATHEMATICA
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Transpose[NestList[Flatten[{Rest[#], ListCorrelate[{5, 5}, #]}]&, {1, 1}, 40]][[1]]
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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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