data/problems/46.yml
---
:id: 46
:name: Goldbach's other conjecture
:url: https://projecteuler.net/problem=46
:content: "It was proposed by Christian Goldbach that every odd composite number can
be written as the sum of a prime and twice a square.\n\n9 = 7 + 2×1<sup>2</sup>
\ \n15 = 7 + 2×2<sup>2</sup> \n21 = 3 + 2×3<sup>2</sup> \n25 = 7 + 2×3<sup>2</sup>
\ \n27 = 19 + 2×2<sup>2</sup> \n33 = 31 + 2×1<sup>2</sup>\n\nIt turns out that
the conjecture was false.\n\nWhat is the smallest odd composite that cannot be written
as the sum of a prime and twice a square?\n\n"