Пример #1
0
def even_fibonacci_mathematical(upper_limit):
    n = int(round(log(upper_limit * sqrt(5)) / log(PSI)))
    last_even_n = n
    if fibonacci(n) % 2 != 0:
        last_even_n = n - 1
        if fibonacci(n - 1) % 2 != 0:
            last_even_n = n - 2

    return sum_of_nth_first_fibonnaci_numbers(last_even_n) / 2
Пример #2
0
def sum_of_nth_first_fibonnaci_numbers(last_even_n):
    return fibonacci(last_even_n + 2) - 1