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41 lines
971 B
Python
41 lines
971 B
Python
"""What is the first term in the Fibonacci sequence to contain 1000 digits?
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The Fibonacci sequence is defined by the recurrence relation:
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Fn = Fn1 + Fn2, where F1 = 1 and F2 = 1.
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Hence the first 12 terms will be:
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F1 = 1
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F2 = 1
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F3 = 2
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F4 = 3
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F5 = 5
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F6 = 8
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F7 = 13
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F8 = 21
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F9 = 34
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F10 = 55
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F11 = 89
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F12 = 144
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The 12th term, F12, is the first term to contain three digits.
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What is the first term in the Fibonacci sequence to contain 1000 digits?
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"""
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def fibonacci(n, limit=None):
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fibonacci = [0, 1]
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i = 2
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while i <= n:
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f = fibonacci[i - 1] + fibonacci[i - 2]
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fibonacci.append(f)
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if limit and f >= limit:
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return (i, fibonacci[-1])
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i = i + 1
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return (n, fibonacci[n])
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def main():
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(term, value) = fibonacci(10**999, 10**999)
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print 'First Fibonacci term with at least 1000 digits is #{0}: {1}'.format(term, value)
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if __name__ == '__main__':
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main()
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