0,1

From 5! on all the factorials end by "zero" thus the persistence is equal to 1.

0!=1; 1!=1; 2!=2; 3!=6 --> Persistence=0

4!=24 --> 2*4=8 --> Persistence=1

5!=120 --> 1*2*0=0 --> Persistence=1

P:=proc(n)local i, k, w, ok, cont; for i from 0 by 1 to n do w:=1; k:=i!; 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. A031346, A130544.

Sequence in context: A011663 A091247 A085137 this_sequence A024360 A025456 A024889

Adjacent sequences: A130540 A130541 A130542 this_sequence A130544 A130545 A130546

easy,nonn

Paolo P. Lava & Giorgio Balzarotti (ppl(AT)spl.at), Jun 04 2007