On the Representation of Fibonacci and Lucas Numbers as the Sum of Three Squares
On the other hand
as is well known
any number
The question of expressing the sequences of Fibonacci and Lucas numbers in the intermediate cases
The question of expressing the sequences of Fibonacci and Lucas numbers in the intermediate cases
n = 2, 3 is also nontrivial. Since F2k+1 = F2
k + F2
k+1, k ธ Z+, then the intersection of the sequence
{Fk}
k=0 and the sequence of sums of two squares of integers is an infinite sequence. At the same
time, the numbers F6k+4, k ธ Z+, cannot be expressed as the sum of two squares of integers, because
F6k+4 ฿ 3 (mod4). Therefore, not all numbers of the form F2k, k ธ Z+, can be expressed as the sum
of two squares. These facts confirm that the problem of expressing the numbers Fk as the sum of two
squares of integers is nontrivial. The problem of expressing the numbers Lk, k ธ Z+ as the sum of two
squares is also nontrivial.