释义 |
Lucas SequenceLet , be Positive Integers. The Roots of
 | (1) |
are
where
 | (4) |
so
Then define
The first few values are therefore
The sequences
are called Lucas sequences, where the definition is usually extended to include
 | (16) |
For , the are the Fibonacci Numbers and are the LucasNumbers. For , the Pell Numbers and Pell-Lucas numbers are obtained. produces the Jacobsthal Numbers and Pell-Jacobsthal Numbers.
The Lucas sequences satisfy the general Recurrence Relations
Taking then gives
Other identities include
These formulas allow calculations for large to be decomposed into a chain in which only four quantities must be kept track ofat a time, and the number of steps needed is . The chain is particularly simple if has many 2s in itsfactorization.
The s in a Lucas sequence satisfy the Congruence
 | (25) |
if
 | (26) |
where
 | (27) |
This fact is used in the proof of the general Lucas-Lehmer Test.See also Fibonacci Number, Jacobsthal Number, Lucas-Lehmer Test, Lucas Number, Lucas PolynomialSequence, Pell Number, Recurrence Sequence, Sylvester Cyclotomic Number References
Dickson, L. E. ``Recurring Series; Lucas' , .'' Ch. 17 in History of the Theory of Numbers, Vol. 1: Divisibility and Primality. New York: Chelsea, pp. 393-411, 1952.Ribenboim, P. The Little Book of Big Primes. New York: Springer-Verlag, pp. 35-53, 1991. |