# Questions tagged [lucas-numbers]

Questions on the Lucas numbers, a special sequence of integers that satisfy the recurrence $L_n=L_{n-1}+L_{n-2}$ with the initial conditions $L_0=2$ and $L_1=1$.

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### Lucas Number Sequence Theorem

How can I prove the following theorem using Induction about Lucas Numbers: $$a_{2n} = a_{n} \, b_{n}$$ Here, $a_{n}$ is the Fibonacci Sequence and $b_{n}$ is the Lucas Sequence. I tried to prove it ...
0answers
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### How can I verify the ratio of Lucas numbers to fibonacci numbers algebreically

The article: "The Lucas numbers 1,3,4...are the sums of alternate Fibonacci numbers. The ratios of Lucas to Fibonacci must satisfy: $R_j = \frac{F_{i+1}+F_{i-1}}{F_i}=\frac{2F_{i+1}}{F_i-1}$ I ...
1answer
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### Lucas sequence equivalent for the tribonacci sequence?

The Fibonacci and Lucas sequences occur within each other's identities, i.e. $$F_{2n} = F_{n} * (F_{n-1} + F_{n+1})$$ $$L_{n} = F_{n-1} + F_{n+1}$$ $$F_{2n} = F_{n} * L_{n}$$ The Lucas sequence ...
0answers
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### if $p\mid u_m$, $m\mid n$, $p\mid u_n/u_m$, prove that $p\mid n/m$

If we have that $p\mid u_a$, $b\mid a$, and $p\mid u_a/u_b$, prove that $p\mid n/b$, assuming that $u_a$ and $u_b$ are terms in the linear recurrence for the Lucas Sequence. I've tried looking at the ...
0answers
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### Extra strong Lucas pseudoprimes and Jacobi symbol

In order to decide out whether a number $n$ is extra strong Lucas pseudoprime, one usually chooses Lucas sequence where Jacobi symbol $(D/n) = -1$. Such a $D$ can be found by Method C by Robert ...
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### Lucas Sequence and primality tests. is this test deterministic?

consider lucas parameters $(P, Q)$ and $D = P^2 - 4Q$. Let $n>0$,$\big(\frac{D}{n}\big)= - 1$ then $U_{n + 1}\equiv{0 \pmod{n}}$ and $n$ is a Lucas probable prime. This test base only on the ...
0answers
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### Is this the best primality test using second order recurrences (Lucas Sequences)?

little Explanation Using second order lucas sequences $$U_{n + 2} = P\cdot{U_{n -1}} - Q\cdot{U_{n}}\qquad U_0=0, U_1=1$$ $$V_{n + 2} = P\cdot{V_{n -1}} - Q\cdot{V_{n}},\qquad V_0=2, V_1=P$$ Now our ...
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### Prove that $\gcd(F_{3K},L_{3k}) \equiv 2$

Following this definition $L_K = F_{K-1} + F_{K+1}$ We have that $\gcd(F_{3K},L_{3k}) = \gcd(F_{3k}, F_{3k+1} + F_{3k-1}) =\gcd(F_{3k}, 2F_{3k-1})$ I don't know where to go from here. How do I ...
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### Proofing that the Lucas numbers come closer to the Phi rounded numbers then the Fibonacci numbers.

Morning everyone, Bit of background, I'm a mid level programmer with very limited mathematics skills. As part of an assessment for a new role I've been asked to complete a technical task which ...