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A189749
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a(1)=5, a(2)=5, a(n)=5*a(n-1) + 5*a(n-2).
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13
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5, 5, 50, 275, 1625, 9500, 55625, 325625, 1906250, 11159375, 65328125, 382437500, 2238828125, 13106328125, 76725781250, 449160546875, 2629431640625, 15392960937500, 90111962890625, 527524619140625, 3088182910156250, 18078537646484375, 105833602783203125
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OFFSET
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1,1
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 1..100
Index entries for linear recurrences with constant coefficients, signature (5, 5).
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FORMULA
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a(n) = 5/2*((5/2+3/2 *sqrt(5))^(n-1)+(5/2-3/2*sqrt(5))^(n-1))+1/2*sqrt(5)*((5/2-3/2*sqrt(5))^(n-1)-(5/2+3/2*sqrt(5))^(n-1)). - Paolo P. Lava, May 24 2011
G.f.: 5*x*(1-4*x)/(1-5*x-5*x^2). - Bruno Berselli, May 24 2011
a(n) = 5*A188168(n). - R. J. Mathar, Feb 13 2020
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MATHEMATICA
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LinearRecurrence[{5, 5}, {5, 5}, 40]
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PROG
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(Maxima) a[1]:5$ a[2]:5$ a[n]:=5*a[n-1]+5*a[n-2]$ makelist(a[n], n, 1, 23); [Bruno Berselli, May 24 2011]
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CROSSREFS
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Cf. A000045, A000079, A105476, A159612, A080040, A135522, A103435, A189732, A189734, A189735, A189736, A189737, A189738, A189739, A189741, A189742, A189743, A189744, A189745, A189746, A189747, A189748.
Sequence in context: A065238 A196388 A073128 * A009390 A009334 A151467
Adjacent sequences: A189746 A189747 A189748 * A189750 A189751 A189752
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KEYWORD
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nonn,easy
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AUTHOR
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Harvey P. Dale, Apr 26 2011
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STATUS
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approved
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