hint: the german versions might be better updated, has a better spelling and style
Persistence in different bases
Persistence of a number
Sascha Kurz 09.10.2001
Abstract: d(n,b) id the product of the digits, in base b, of n. Example: d(329,10)=3*2*9=54. The Persistence p(n,b) id the number of steps you can nest the above function d to n, so that the last result has only 1 digit. Example: p(329,10)=3.
