# Project Euler 47

Problem47を解きました．

• Distinct primes factors

The first two consecutive numbers to have two distinct prime factors are:

14 = 2 × 7
15 = 3 × 5

The first three consecutive numbers to have three distinct prime factors are:

644 = 2² × 7 × 23
645 = 3 × 5 × 43
646 = 2 × 17 × 19.

Find the first four consecutive integers to have four distinct prime factors. What is the first of these numbers?

https://projecteuler.net/problem=47

```require 'prime'

i = 2
k = 4
loop do
div1 = []
div2 = []
div3 = []
factors1 = Prime.prime_division(i)
if factors1.length != k
i += 1
next
end
factors2 = Prime.prime_division(i + 1)
if factors2.length != k
i += 1
next
end
factors3 = Prime.prime_division(i + 2)
if factors3.length != k
i += 1
next
end
factors4 = Prime.prime_division(i + 3)
if factors4.length != k
i += 1
next
end

for j in 0..k - 1 do
div1.push(factors1[j][0])
div1.push(factors2[j][0])
div2.push(factors2[j][0])
div2.push(factors3[j][0])
div3.push(factors3[j][0])
div3.push(factors4[j][0])
end

div1.sort!.uniq!
div2.sort!.uniq!
div3.sort!.uniq!

unless div1.length == k * 2 && div2.length == k * 2 && div3.length == k * 2
i += 1
next
end
p i
break
end
```