A206612 Fibonacci sequence beginning 13, 6.
13, 6, 19, 25, 44, 69, 113, 182, 295, 477, 772, 1249, 2021, 3270, 5291, 8561, 13852, 22413, 36265, 58678, 94943, 153621, 248564, 402185, 650749, 1052934, 1703683, 2756617, 4460300, 7216917, 11677217, 18894134, 30571351, 49465485, 80036836, 129502321
Offset: 1
Links
- Vincenzo Librandi, Table of n, a(n) for n = 1..1000
- Index entries for linear recurrences with constant coefficients, signature (1, 1).
Programs
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Magma
I:=[13, 6]; [n le 2 select I[n] else Self(n-1)+Self(n-2): n in [1..40]]; // Vincenzo Librandi, Feb 17 2012
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Mathematica
LinearRecurrence[{1, 1}, {13, 6}, 80] -
PARI
Vec((13 - 7*x)/(1 - x - x^2) + O(x^30)) \\ Andrew Howroyd, Aug 28 2018
Formula
From Andrew Howroyd, Aug 28 2018: (Start)
a(n) = a(n-1) + a(n-2) for n > 2.
a(n) = 13*Fibonacci(n) - 7*Fibonacci(n-1).
G.f.: x*(13 - 7*x)/(1 - x - x^2).
(End)