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A049656
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a(n) = (F(8n+7)-1)/3, where F=A000045 (the Fibonacci sequence).
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3
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4, 203, 9552, 448756, 21081995, 990405024, 46527954148, 2185823439947, 102687173723376, 4824111341558740, 226630545879537419, 10646811544996699968, 500173512068965361092, 23497508255696375271371, 1103882714505660672393360, 51858990073510355227216564
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OFFSET
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0,1
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LINKS
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FORMULA
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G.f.: ( -4-11*x ) / ( (x-1)*(x^2-47*x+1) ). - R. J. Mathar, Oct 26 2015
a(n) = (-1+((94+42*sqrt(5))^(-n)*(4^n*(1+sqrt(5))+2*(47+21*sqrt(5))^(2*n)*(682+305*sqrt(5))))/(105+47*sqrt(5)))/3. - Colin Barker, Mar 06 2016
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MATHEMATICA
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RecurrenceTable[{a[0] == 4, a[1] == 203, a[n] == 47 a[n-1] - a[n-2] + 15}, a, {n, 30}] (* Vincenzo Librandi, Mar 06 2016 *)
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PROG
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(PARI) Vec((-4-11*x)/((x-1)*(x^2-47*x+1)) + O(x^25)) \\ Colin Barker, Mar 06 2016
(Magma) I:=[4, 203]; [n le 2 select I[n] else 47*Self(n-1)-Self(n-2)+15: n in [1..30]]; // Vincenzo Librandi, Mar 06 2016
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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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