39 lines
638 B
Ruby
39 lines
638 B
Ruby
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descr=%{
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The Fibonacci sequence is defined by the recurrence relation:
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F_(n) = F_(n−1) + F_(n−2), where F_(1) = 1 and F_(2) = 1.
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Hence the first 12 terms will be:
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F_(1) = 1
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F_(2) = 1
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F_(3) = 2
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F_(4) = 3
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F_(5) = 5
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F_(6) = 8
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F_(7) = 13
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F_(8) = 21
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F_(9) = 34
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F_(10) = 55
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F_(11) = 89
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F_(12) = 144
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The 12th term, F_(12), 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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n=3
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i=1
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j=1
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f=i+j
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while f.to_s.length<1000
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# while n<5
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n+=1
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i=j
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j=f
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f=i+j
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# puts %{#{n}, #{f}}
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end
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puts n
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