原题链接http://projecteuler.net/problem=46

Goldbach’s other conjecture

It was proposed by Christian Goldbach that every odd composite number can be written as the sum of a prime and twice a square.

9 = 7 + 21²
15 = 7 + 22²
21 = 3 + 23²
25 = 7 + 23²
27 = 19 + 22²
33 = 31 + 21²

It turns out that the conjecture was false.

What is the smallest odd composite that cannot be written as the sum of a prime and twice a square?

哥德巴赫的另一个猜想
这个猜想是克里斯蒂安.哥德巴赫提出的，它是这样的：任意一个合数，如果是奇数的话，则可以写成一个素数与一个平方数的两倍的和
9 = 7 + 21²
15 = 7 + 22²
21 = 3 + 23²
25 = 7 + 23²
27 = 19 + 22²
33 = 31 + 21²
结果这个猜想是错的。
求最小的不能写成一个素数与一个平方数的两倍的和的奇合数​

解答：
还是暴力吧。