0,9

10! = 10*9*8*7*6*5*4*3*2 = 3628800 -> 3+6+2+8+8 = 27 -> 2+7 = 9 -> persistence = 2.

P:=proc(n)local i, k, w, ok, cont; for i from 1 by 1 to n do k:=i!; w:=0; ok:=1; 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);

Cf. A000142.

Sequence in context: A032552 A087717 A053444 this_sequence A135717 A079083 A032568

Adjacent sequences: A130632 A130633 A130634 this_sequence A130636 A130637 A130638

easy,nonn,base

Paolo P. Lava & Giorgio Balzarotti (ppl(AT)spl.at), Jun 19 2007, corrected Jun 22 2007