A136761 - OEIS

%I #16 Jan 15 2021 16:32:38

%S 1,1,2,6,2,10,5,3,2,2,2,2,2,2,3,4,6,10,1,2,4,9,1,3,7,1,3,9,2,5,1,3,1,

%T 3,9,2,9,2,9,3,1,3,1,5,1,7,2,1,4,1,9,3,1,7,3,1,8,3,1,9,4,2,1,7,3,2,1,

%U 6,3,2,1,8,4,2,1,1,7,4,3,2,1,10,6,4,3,2,1,1,9,6,5,3,2,2,1,1,1,9,7,6

%N a(n) = leading digit of n! in base 11.

%H David A. Corneth, <a href="/A136761/b136761.txt">Table of n, a(n) for n = 0..9999</a>

%e a(10) = 2 as 10! = 20594010_11 which has leading digit 2. - _David A. Corneth_, Jan 15 2021

%t f[n_]:=First[IntegerDigits[n!,11]]; lst={};Do[AppendTo[lst,f[n]],{n,0,2*5!}];lst (* _Vladimir Joseph Stephan Orlovsky_, Jun 14 2009 *)

%t First[IntegerDigits[#,11]]&/@(Range[0,100]!) (* _Harvey P. Dale_, Feb 20 2013 *)

%o (PARI) a(n) = digits(n!, 11)[1]; \\ _Michel Marcus_, Jan 27 2015

%Y Cf. A000142, A136697, A136754, A136755, A136756, A136757, A136758, A136759, A136760, A008905, A136762, A136763, A136764, A136765, A136766.

%K nonn,easy,base

%O 0,3

%A _Carl R. White_, Jan 21 2008