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A103326
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a(n) = Fibonacci(5n)/Fibonacci(n).
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1
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5, 55, 305, 2255, 15005, 104005, 709805, 4873055, 33379505, 228841255, 1568358005, 10750060805, 73681030805, 505019869255, 3461450947505, 23725155368255, 162614587921805, 1114577087604805, 7639424691459005
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OFFSET
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1,1
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LINKS
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Table of n, a(n) for n=1..19.
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FORMULA
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a(n) = L(4n) + (-1)^n*L(2n) + 1, where L(n) = A000032, the Lucas numbers.
a(n) = 1 + L(n)*L(3n). - Neven Juric, Jan 05 2009
a(n) = 25*(Fibonacci(n)^4 + (-1)^n*Fibonacci(n)^2) + 5. [Gary Detlefs, Dec 22 2012]
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MAPLE
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p:= (1+5^(1/2))/2:q:=(1-5^(1/2))/2:
seq(simplify(q^(4*n)+(p-2)^n+(q-2)^n+(3*p+2)^n+(-1)^(2*n)/4+3/4), n=1..19);
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PROG
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(MAGMA) [Fibonacci(5*n)/Fibonacci(n): n in [1..50]]; // Vincenzo Librandi, Apr 20 2011
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CROSSREFS
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Fourth row of array A028412.
Sequence in context: A057722 A078216 A014700 * A060558 A014852 A144893
Adjacent sequences: A103323 A103324 A103325 * A103327 A103328 A103329
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KEYWORD
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nonn
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AUTHOR
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Ralf Stephan, Feb 03 2005
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STATUS
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approved
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