diff --git a/README.md b/README.md
index dce94f8..771fd93 100644
--- a/README.md
+++ b/README.md
@@ -14,4 +14,9 @@ Each new term in the Fibonacci sequence is generated by adding the previous two
 1, 2, 3, 5, 8, 13, 21, 34, 55, 89,
 By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.
 
-# Euler problem 3 :
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+# Euler problem 3 :
+
+The prime factors of 13195 are 5, 7, 13 and 29
+What is the largest prime factor of the number 600851475143
+
+[wiki](https://baobabfruit.ddns.net/en/code/project-euler/prime-numbers)
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