It is conjectured that 196 and other numbers which have not yet yielded a palindrome are Lychrel numbers, but no number has yet been proven to be Lychrel.

• 由于目前还不可能证明一个数永远不能形成回文数，所以“196 和其他那些（看起来）不能形成回文数的数是利克瑞尔数”这一命题仅是猜想而非已获证明。