問題 What is the smallest number divisible by each of the numbers 1 to 20? 英語 2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder.What is the smallest number that is evenly divisible …

問題 Find the largest palindrome made from the product of two 3-digit numbers. 英語 A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 × 99.Find the largest palin…

問題 Find the largest prime factor of a composite number. 英語 The prime factors of 13195 are 5, 7, 13 and 29.What is the largest prime factor of the number 600851475143 ? http://projecteuler.net/index.php?section=problems&id=3 日本語 1319…

問題 Find the sum of all the even-valued terms in the Fibonacci sequence which do not exceed four million. 英語 Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 t…

今までソースコード載っける気がなかったけど羊が載せてるのでこっちも晒してみることにした。 しかし、先に始めてたはずなのに完全に羊の後追いになってるな現状 プログラミング能力に差もあるんだが、業務中もやられると太刀打ちできんw まぁ、Ruby使って…

問題 Add all the natural numbers below one thousand that are multiples of 3 or 5. 英語 If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.Find the sum of all the…