全循環質數 在數論中全循環質數又名長質數是指一個質數p使分數p的循環節長度比質數少更精確地說全循環質數是指一個質數p在一個已知底數為b的進位制下在下面算式中可以得出一個循環數的質數 b p     p displaystyle frac bpp 若p為b為所得的數字CAFEDGBBE為循環數 CAFEDGBBE    CAFEDGBBE CAFEDGBBE    BECAFEDGB CAFEDGBBE    BECAFEDGB CAFEDGBBE    GBBECAFED CAFEDGBBE    BECAFEDGB CAFEDGBBE    BBECAFEDG CAFEDGBBE    GBBECAFED CAFEDGBBE    FEDGBBECA CAFEDGBBE    BBECAFEDG CAFEDGBBE  A  BBECAFEDG CAFEDGBBE  B  BECAFEDGB CAFEDGBBE  C  EDGBBECAF CAFEDGBBE  D  AFEDGBBEC CAFEDGBBE  E  AFEDGBBEC CAFEDGBBE  F  BBECAFEDG CAFEDGBBE  G  BECAFEDGB CAFEDGBBE    CAFEDGBBE CAFEDGBBE    DGBBECAFE CAFEDGBBE    ECAFEDGBB CAFEDGBBE    EDGBBECAF CAFEDGBBE    FEDGBBECA CAFEDGBBE    GBBECAFED 而      C  A  F  E D  G  B  B E  displaystyle  over overline CAFEDGBBE 循環節長度為比少因此為全循環質數 十進位中的全循環質數有                                          OEIS數列A