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

Permalink: https://projecteuler.net/problem=25

We’ve introduced Fibonacci sequence at Clojure Euler: Problem 002

Lazy sequence generates fibonacci numbers is dead simple:

```
(defn fibonacci []
(->> [0 1]
(iterate (fn [[a b]] [b (+' a b)]))
(map first)))
```

We also can count the length of number in digits. No decimal arithmetic. Cast number to string, and take length of a string

```
(defn num-of-digits [n]
(count (str n)))
```

To solve the problem use the most straightforward approach and you’ll find the answer in less than 1 second.

```
(->> (fibonacci)
(map-indexed (fn [i n] [i (num-of-digits n)]))
(drop-while #(< (second %) 1000))
(first)
(first))
```

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