９倍自己再現数の末尾は４，５，９のいすれかである．

＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝

　　９（０５）^2＝２２５

　　９（１５）^2＝２０２５

　　９（２５）^2＝５６２５

下２桁は２５となる．

　　９（０２５）^2＝５６２５

　　９（１２５）^2＝１４０６２５

　　９（２２５）^2＝４５６６２５

下３桁は６２５となる．

　　９（０６２５）^2＝３５１５６２４

　　９（１６２５）^2＝２３７６５６２５

　　９（２６２５）^2＝６２０１５６２５

下４桁は５６２５となる．

＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝