Problem 25 - What is the first term in the Fibonacci sequence to contain 1000 digits?

링크

The Fibonacci sequence is defined by the recurrence relation:

F_n = F_n1 + F_n2, where F₁ = 1 and F₂ = 1.

Hence the first 12 terms will be:

F₁ = 1
F₂ = 1
F₃ = 2
F₄ = 3
F₅ = 5
F₆ = 8
F₇ = 13
F₈ = 21
F₉ = 34
F₁₀ = 55
F₁₁ = 89
F₁₂ = 144

The 12th term, F₁₂, is the first term to contain three digits.

What is the first term in the Fibonacci sequence to contain 1000 digits?

python

f1 = 1 f2 = 1 term = 3 while len(str(f1 + f2)) < 1000: f1, f2 = f2, f1+ f2 term += 1 print term