OFFSET
0,10
EXAMPLE
229 -> 2*2*9=36 -> 3*6=18 -> 1*8=8 -> persistence = 3
MAPLE
P:=proc(n) local i, k, w, ok, cont, x; for i from 1 by 1 to n do k:=ithprime(i); w:=1; ok:=1; x:=k; if k<10 then print(0); else cont:=1; while ok=1 do while k>0 do w:=w*(k-(trunc(k/10)*10)); k:=trunc(k/10); od; if w<10 then ok:=0; print(cont); else cont:=cont+1; k:=w; w:=1; fi; od; fi; od; end: P(100);
CROSSREFS
KEYWORD
easy,nonn,base
AUTHOR
Paolo P. Lava and Giorgio Balzarotti, Jun 14 2007
STATUS
approved